Generally speaking, you can only even attempt to use a “trained only” skill if you have at least one rank in it (for some skills there are exceptions or ways to get around it, the most common one that comes up being that you can make Knowledge checks with a DC of 10 or less untrained)
Almost always yes, but there are a couple small differences:
- Eschew Materials applies to spells with a listed component cost of 1 GP or less, whereas a spell component pouch is only assumed to cover spells with no listed component cost, and there are a handful of spells where the distinction matters
- A spell component pouch is assumed to contain “focus” components too (the ones listed as “F” in a spell description), whereas Eschew Materials only applies to “material” components
- Generally speaking, the difference is that “Material” components are consumed when the spell is cast, whereas “Focus” components are not consumed and can be reused. (tangent: there are a handful of poorly written spells, mostly from the more-distant-from-Core books, where the material component probably was basically intended to be a focus component – for example, Appearance of Life is probably not intended to “consume” the creature used as a component
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- Generally speaking, the difference is that “Material” components are consumed when the spell is cast, whereas “Focus” components are not consumed and can be reused. (tangent: there are a handful of poorly written spells, mostly from the more-distant-from-Core books, where the material component probably was basically intended to be a focus component – for example, Appearance of Life is probably not intended to “consume” the creature used as a component
- since a spell component pouch is a physical object, you need to be able to manipulate it (so you couldn’t use it if both your hands were full), + it could in principle be lost or stolen
- some people don’t like imagining that their character is carrying around hundreds of tiny rags to spam Resistance, or whatever
Sorcerers get Eschew Materials automatically, and for spells with a costless focus component I’m fine with just assuming you start with that component
sidenote
you might see some spells that list “M/DF” – what that means is that arcane casters cast it with the material component, while divine casters use their holy symbol as a focus component (or some appropriate equivalent, for divine casters who don’t get their powers from a god)
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