A spellcasting focus can be used in place of a material component only if that component has no cost noted in the spell’s description and if that component isn’t consumed.
Does spellcasting focus replace material components?
The primary purpose of a spellcasting focus is to replace the non-costly material components of your spells. If it has a listed price in the spell description, you must still provide that material component – ex.
Can you use a component pouch as a focus?
They’re functionally equivalent for a single-classed spellcaster. A character can use a component pouch or a spellcasting focus (found in “Equipment”) in place of the components specified for a spell. But if a cost is indicated for a component, a character must have that specific component before he or she can cast the spell.
What’s the difference between a focus and a foci?
As you’ve said, for any material component without a cost, a Focus can substitute. The only mechanical difference is that a component pouch costs twice as much as the cheaper foci. However, flavor-wise, there’s quite the difference. A caster using their focus has quite a different air about them than one pulling the components from their bag.
What’s the difference between an arcane focus and component pouch?
As you have noted, the primary function of both an arcane focus and a component pouch is to replace the non-costly material components of a spell. The biggest difference was clarified in the rules of spellcasting sage advice. The following question was asked:
What’s the difference between a focus and a war caster?
The War Caster feat lets you get around the issue for somatic components, by the way. Mechanically, not much of a difference. As you’ve said, for any material component without a cost, a Focus can substitute. The only mechanical difference is that a component pouch costs twice as much as the cheaper foci.
