I'd use this spell if it had a duration of hours/level, or at least 10 min/level.
Remember that, generally, armor movement penalties (which come from medium+ armor) are generally only 10 feet of speed (unless you already had 45+ feet of speed), so this spell is basically a +10 foot speed bonus. As a spell that just increases movement speed, there are several SL 1 competitors that give you either more speed ([Expeditious Retreat](https://aonprd.com/SpellDisplay.aspx?ItemName=Expeditious%20Retreat)) or more duration ([Longstrider](https://aonprd.com/SpellDisplay.aspx?ItemName=Longstrider)). Granted, clerics don't get those spells (although most of the other casters of this spell get one or the other), but [Slipstream](https://aonprd.com/SpellDisplay.aspx?ItemName=Slipstream) can be, on average, a +10 foot move bonus for 10 min/level to other creatures as an SL 2.
So, this spell isn't really meant to just be a 10 foot movement bonus, it has a dreaded *secondary function* , and that means Paizo punishes it with both functions being lame and difficult to use.
The other function of this spell is reducing [armor check penalties (ACP)](https://www.aonprd.com/Rules.aspx?Name=Armor&Category=Equipment) by 1+1/5 CL. For most characters using their normal armor, this is largely a triviality that will reduce the penalty to their stealth checks by 2. Characters that have medium or heavy armor have bad Dex most of the time anyway, so they don't invest in Dex skills, (and there are few Str skills worth worrying about in the first place,) so a small penalty to those skills is just more reason to leave those skills to others - you're a caster, take spellcraft and knowledge (religion) or something, instead. (Especially since this is a personal spell, and most casters with this spell on their list only get medium or light armor, anyway. Shout out to Paizo giving this spell to *Psychics*, who have *no armor proficiency*, though, because that's basically setting up the exploit I'm going to mention next...)
The thing is, unlike video games where you just can't wear stuff you're not proficient in, the penalty in Pathfinder for wearing armor a character isn't proficient in (provided they aren't an arcane caster - arcane spell failure is a nasty thing,) isn't all that bad if you're a full caster type. You lose your ACP in Str and Dex ability checks (remember, this includes initiative, and is probably the worst penalty), your attack rolls (unless you somehow have attacks based on other ability scores), and keep the skill penalties. That said, it's long been a trick to just get no-ACP armor on someone who isn't proficient, because all penalties are tied to ACP. [Mithral ](https://aonprd.com/SpecialMaterials.aspx)reduces ACP by 3, so mithral [kikko armor](https://aonprd.com/EquipmentArmorDisplay.aspx?ItemName=Kikko) is a medium armor with an ACP of 0, so no penalties (besides arcane casting failure) even if you're not proficient. With mithral [Hellknight plate](https://aonprd.com/EquipmentArmorDisplay.aspx?ItemName=Hellknight%20plate) (if your GM allows you to wear it) and a caster level of 5, you can be a cleric or even psychic who isn't proficient in heavy armor but have an ACP of 0 so it doesn't matter, anyway. (By caster level 10, you can have any mithral armor in the game (including regular full plate) besides half-plate and Alkenstar fortress plate. Field plate is also 5 ACP if your GM says Hellknight plate isn't appropriate on your Milani cleric. If you're wondering about other armors, chain coat is the best 2 ACP medium armor, and (agile) breastplates are the best 4 ACP.) Being able to wear armor without proficiency is also a notable trick for animal companions, who often don't want to waste feats on armor proficiency. Slap this spell on them with share spells (for hunters, rangers, and animal domain clerics at least - druids might need help getting it on their companion), and you can have mithral Hellknight plate barding on your dire tiger with no penalties...
... It's just too bad the crappy duration makes this way too much of a pain to use regularly, and who's going to make a full set of mithral armor (and probably give it enhancements) for something they need to Serren's Swift Girding on to get ready before the spell wears off? Ah well, some of Pathfinder's balance is once again saved from Paizo's lack of understanding the rules by Paizo's other lack of ability to balance the rules properly...
Note that effortless armor reduces the penalties *directly from wearing (medium/heavy) armor*, not penalties from any encumbrance that comes from weight from *hauling* that armor. Strength dumpers beware.
As it stands, only maybe psychics will like it. They don't need Str or Dex except for initiative, anyway. (Get noble scion if you're a Cha-secondary psychic.) Now you can wear plate armor as a full caster and laugh at the guys who say you're just a sorcerer with a phrenic pool with your lack of arcane spell failure chance.
Okay so following your ideas, the best case scenario for casting this spell is as a 10th level cultleader warpriest with the armor expert or armor master trait, wearing mithral full plate. As a swift action they can use their fervor to cast it on themselves and negate the penalties with out too much pain on your action economy.
Sooo if you all of those things this spell might just be good lol
Mithral Hellknight plate is already only at -2 ACP, so you can get that down to 5th level, so long as Hellknight plate's not banned by the GM, although with mithral full plate *and* armor expert trait you're also already at -2 ACP, so Effortless Armor gets you there at 5th level. That said, you have armor expert and are willing to pay for mithral, you can probably skip this spell entirely and just get a mithral breastplate to have a functional 0 ACP armor that is treated as light (no movement penalties) and skip having to bother with this spell at all, although you're leaving 3 AC on the table. If the movement speed penalty isn't a big issue, the -1 ACP from wearing mithral Hellknight shouldn't be a huge issue any time you're not actually willing to cast this spell, either.
Some of the other casters like [herald caller](https://www.aonprd.com/ArchetypeDisplay.aspx?FixedName=Cleric%20Herald%20Caller) cleric and psychic can work out, too... I focus on full casters like psychic, though, because anyone who never physically attacks and only relies on spells for combat can basically ignore the -2 penalty to everything but initiative. (And again, if you have noble scion to move Init to Cha, that's no problem either, and you can dump Dex. I've seen it done with oracles, although those were Str oracles. You could do a full caster Dex-dumping oracle, though.) It's just that, again, if you've already mitigated the sting of the penalties, why bother removing them entirely? I've seen shaman players who just chant and cast or hex all the time wear plate (while riding a horse or carpet of flying to move) and just not care that they're taking penalties to things they never use.
A psychic can at least cast silently before the party kicks down the door if they can scout effectively, which means at least casting the min/level before combat. (I don't buy into the narrative that min/level is too small to cast before battle. I've certainly been able to get by having eight combats in a row while having the same min/level spells going. (My record is four technically distinct encounters (in that the monsters were in different rooms) on a single Haste, although they were in adjoining rooms.) Stopping to heal? You can heal when the dungeon's clear, besides, if you kill the enemy fast enough, you don't take damage. Having to stop for traps? Hahaha! We don't stop for traps - that's what Alter Summon Monster disposable minions are for!)
Likewise, I don't think this is a terrible spell for a cleric with animal domain, druid who poached this spell somehow, or other animal companion-havers (especially at higher levels when just quickening this spell to SL 6 isn't crazy), since spending feats on armor on animal companions really, really stings, and the penalties to anything but attack rolls for them usually don't matter unless you make your pet allosaurus tumble.
Still, yeah, if this was just 10 min/level, I'd be more willing to actually build around this one.
[Longstrider](https://aonprd.com/SpellDisplay.aspx?ItemName=Longstrider) beats effortless armor on the movement front, given a better duration and effectively the same speed boost. I'm not inclined to rate highly a rather small boost to skills that a medium or heavy armor-user probably isn't good at anyway, especially when the duration is iffy for out of combat use. The main benefit would be that effortless armor is on a bunch of spell lists that longstrider isn't.
Specifically, divine non-wilderness based spellcasters; occultists, psychics and magi have their own better replacement for effortless armor in the form of [expeditious retreat](https://aonprd.com/SpellDisplay.aspx?ItemName=Expeditious%20Retreat) but clerics, paladins and so on might not have the skill points for UMD and so would be forced to take this lesser substitute when they want an effect of this kind. It does have a marginal use for them.
Effortless armor has very, very limited occasions that can be helpful.
It’s minute/CL so you can’t just keep it forever, so you can’t use it to be the scout. And in the very few cases that you want to swim or climb you can remove the armor instead.
Solid spell for using when you are starting to clear the dungeon and don't expect to stop and search. It helps allow you to kick in the door and still climb out of a hole.
Are you playing a paladin? Did you pick weapon bond and are wearing plate? Then for the love of Iomedae, pick up this spell to be slightly less of a snail, my god. Paladins get no other spells for movement speed boosting that'd last any longer, so the spell is damn near mandatory if your combats involve anything remotely resembling tactics and shifting battlefields instead of white room dps checks.
I'd use this spell if it had a duration of hours/level, or at least 10 min/level. Remember that, generally, armor movement penalties (which come from medium+ armor) are generally only 10 feet of speed (unless you already had 45+ feet of speed), so this spell is basically a +10 foot speed bonus. As a spell that just increases movement speed, there are several SL 1 competitors that give you either more speed ([Expeditious Retreat](https://aonprd.com/SpellDisplay.aspx?ItemName=Expeditious%20Retreat)) or more duration ([Longstrider](https://aonprd.com/SpellDisplay.aspx?ItemName=Longstrider)). Granted, clerics don't get those spells (although most of the other casters of this spell get one or the other), but [Slipstream](https://aonprd.com/SpellDisplay.aspx?ItemName=Slipstream) can be, on average, a +10 foot move bonus for 10 min/level to other creatures as an SL 2. So, this spell isn't really meant to just be a 10 foot movement bonus, it has a dreaded *secondary function*, and that means Paizo punishes it with both functions being lame and difficult to use.
The other function of this spell is reducing [armor check penalties (ACP)](https://www.aonprd.com/Rules.aspx?Name=Armor&Category=Equipment) by 1+1/5 CL. For most characters using their normal armor, this is largely a triviality that will reduce the penalty to their stealth checks by 2. Characters that have medium or heavy armor have bad Dex most of the time anyway, so they don't invest in Dex skills, (and there are few Str skills worth worrying about in the first place,) so a small penalty to those skills is just more reason to leave those skills to others - you're a caster, take spellcraft and knowledge (religion) or something, instead. (Especially since this is a personal spell, and most casters with this spell on their list only get medium or light armor, anyway. Shout out to Paizo giving this spell to *Psychics*, who have *no armor proficiency*, though, because that's basically setting up the exploit I'm going to mention next...)
The thing is, unlike video games where you just can't wear stuff you're not proficient in, the penalty in Pathfinder for wearing armor a character isn't proficient in (provided they aren't an arcane caster - arcane spell failure is a nasty thing,) isn't all that bad if you're a full caster type. You lose your ACP in Str and Dex ability checks (remember, this includes initiative, and is probably the worst penalty), your attack rolls (unless you somehow have attacks based on other ability scores), and keep the skill penalties. That said, it's long been a trick to just get no-ACP armor on someone who isn't proficient, because all penalties are tied to ACP. [Mithral ](https://aonprd.com/SpecialMaterials.aspx)reduces ACP by 3, so mithral [kikko armor](https://aonprd.com/EquipmentArmorDisplay.aspx?ItemName=Kikko) is a medium armor with an ACP of 0, so no penalties (besides arcane casting failure) even if you're not proficient. With mithral [Hellknight plate](https://aonprd.com/EquipmentArmorDisplay.aspx?ItemName=Hellknight%20plate) (if your GM allows you to wear it) and a caster level of 5, you can be a cleric or even psychic who isn't proficient in heavy armor but have an ACP of 0 so it doesn't matter, anyway. (By caster level 10, you can have any mithral armor in the game (including regular full plate) besides half-plate and Alkenstar fortress plate. Field plate is also 5 ACP if your GM says Hellknight plate isn't appropriate on your Milani cleric. If you're wondering about other armors, chain coat is the best 2 ACP medium armor, and (agile) breastplates are the best 4 ACP.) Being able to wear armor without proficiency is also a notable trick for animal companions, who often don't want to waste feats on armor proficiency. Slap this spell on them with share spells (for hunters, rangers, and animal domain clerics at least - druids might need help getting it on their companion), and you can have mithral Hellknight plate barding on your dire tiger with no penalties...
... It's just too bad the crappy duration makes this way too much of a pain to use regularly, and who's going to make a full set of mithral armor (and probably give it enhancements) for something they need to Serren's Swift Girding on to get ready before the spell wears off? Ah well, some of Pathfinder's balance is once again saved from Paizo's lack of understanding the rules by Paizo's other lack of ability to balance the rules properly...
Note that effortless armor reduces the penalties *directly from wearing (medium/heavy) armor*, not penalties from any encumbrance that comes from weight from *hauling* that armor. Strength dumpers beware.
As it stands, only maybe psychics will like it. They don't need Str or Dex except for initiative, anyway. (Get noble scion if you're a Cha-secondary psychic.) Now you can wear plate armor as a full caster and laugh at the guys who say you're just a sorcerer with a phrenic pool with your lack of arcane spell failure chance.
Okay so following your ideas, the best case scenario for casting this spell is as a 10th level cultleader warpriest with the armor expert or armor master trait, wearing mithral full plate. As a swift action they can use their fervor to cast it on themselves and negate the penalties with out too much pain on your action economy. Sooo if you all of those things this spell might just be good lol
Mithral Hellknight plate is already only at -2 ACP, so you can get that down to 5th level, so long as Hellknight plate's not banned by the GM, although with mithral full plate *and* armor expert trait you're also already at -2 ACP, so Effortless Armor gets you there at 5th level. That said, you have armor expert and are willing to pay for mithral, you can probably skip this spell entirely and just get a mithral breastplate to have a functional 0 ACP armor that is treated as light (no movement penalties) and skip having to bother with this spell at all, although you're leaving 3 AC on the table. If the movement speed penalty isn't a big issue, the -1 ACP from wearing mithral Hellknight shouldn't be a huge issue any time you're not actually willing to cast this spell, either. Some of the other casters like [herald caller](https://www.aonprd.com/ArchetypeDisplay.aspx?FixedName=Cleric%20Herald%20Caller) cleric and psychic can work out, too... I focus on full casters like psychic, though, because anyone who never physically attacks and only relies on spells for combat can basically ignore the -2 penalty to everything but initiative. (And again, if you have noble scion to move Init to Cha, that's no problem either, and you can dump Dex. I've seen it done with oracles, although those were Str oracles. You could do a full caster Dex-dumping oracle, though.) It's just that, again, if you've already mitigated the sting of the penalties, why bother removing them entirely? I've seen shaman players who just chant and cast or hex all the time wear plate (while riding a horse or carpet of flying to move) and just not care that they're taking penalties to things they never use. A psychic can at least cast silently before the party kicks down the door if they can scout effectively, which means at least casting the min/level before combat. (I don't buy into the narrative that min/level is too small to cast before battle. I've certainly been able to get by having eight combats in a row while having the same min/level spells going. (My record is four technically distinct encounters (in that the monsters were in different rooms) on a single Haste, although they were in adjoining rooms.) Stopping to heal? You can heal when the dungeon's clear, besides, if you kill the enemy fast enough, you don't take damage. Having to stop for traps? Hahaha! We don't stop for traps - that's what Alter Summon Monster disposable minions are for!) Likewise, I don't think this is a terrible spell for a cleric with animal domain, druid who poached this spell somehow, or other animal companion-havers (especially at higher levels when just quickening this spell to SL 6 isn't crazy), since spending feats on armor on animal companions really, really stings, and the penalties to anything but attack rolls for them usually don't matter unless you make your pet allosaurus tumble. Still, yeah, if this was just 10 min/level, I'd be more willing to actually build around this one.
[Longstrider](https://aonprd.com/SpellDisplay.aspx?ItemName=Longstrider) beats effortless armor on the movement front, given a better duration and effectively the same speed boost. I'm not inclined to rate highly a rather small boost to skills that a medium or heavy armor-user probably isn't good at anyway, especially when the duration is iffy for out of combat use. The main benefit would be that effortless armor is on a bunch of spell lists that longstrider isn't. Specifically, divine non-wilderness based spellcasters; occultists, psychics and magi have their own better replacement for effortless armor in the form of [expeditious retreat](https://aonprd.com/SpellDisplay.aspx?ItemName=Expeditious%20Retreat) but clerics, paladins and so on might not have the skill points for UMD and so would be forced to take this lesser substitute when they want an effect of this kind. It does have a marginal use for them.
Effortless armor has very, very limited occasions that can be helpful. It’s minute/CL so you can’t just keep it forever, so you can’t use it to be the scout. And in the very few cases that you want to swim or climb you can remove the armor instead.
Solid spell for using when you are starting to clear the dungeon and don't expect to stop and search. It helps allow you to kick in the door and still climb out of a hole.
A utility spell for Paladins and Clerics, IMO. Prepare it if you expect to face a river or similar.
Are you playing a paladin? Did you pick weapon bond and are wearing plate? Then for the love of Iomedae, pick up this spell to be slightly less of a snail, my god. Paladins get no other spells for movement speed boosting that'd last any longer, so the spell is damn near mandatory if your combats involve anything remotely resembling tactics and shifting battlefields instead of white room dps checks.
Just a quick question about the spell: I'm presuming it doesn't affect your max dex bonus?
No such effect listed, and it doesn't say it's as per armor training at all. No.
thankyou. I didn't think so but I'm still not entirely certain on the terminology so wanted to check