thats the most you would be taking off basically.
it kinda depends on the fret size, what string gauge you are used to using and how deep the indents are in the first place. most of the time its about the size of construction paper, granted im thinking more of a 10-15 year old guitar.
somewhere i have pics of a few 25+ year old guitar necks that i literally had to take off half of the fret and cut the nut deeper(slightly) to get them proper.
