Is it possible to either make a magic item with more uses per day than the standard version, or to add more uses later?
For example, the new Pelt of the Beast from Blood of the Moon allows one to turn into the animal the pelt is from 3/day.
Would it be reasonable to increase the cost of it to make it at will, or to have it enhanced to be at will?
More so the reason I am asking is I'm more thinking about it as an upgraded version with the Legendary Item thing from Mythic Adventures.
The generic formula for 'X uses per day' magic items is that you take the cost for a continuous version of the item, divide by 5, then multiply by the number of times per day it will work. So, if the continuous version costs 10,000 gp, the version which works once per day costs 2,000 gp. Thrice per day is 6,000 gp. You get the idea.
Don't forget about the time factor multiplier for continuous. However, it is different if you want use-on-command with no limit. That is SL*CL*1,800 + material component cost, but each use would last the same as the non-at will version.
/cevah