The Hub

I finished levelling frets on a mandolin last week, and was surprised that the frets with the worst divots worked down to .020" Had I known that I'd go that low, I might have replaced them, but it's hard to measure divot height, especially those caused by thin strings.

I haven't seen much discussion on standards for fret height or guidelines to know at what point should I switch from levelling to replacement. What standards are people using??