How do you know when you need to do a re-fret?

Hi.

The frets have to be replaced when fret levelling and re-crowning can't restore the playability You're used to. The playability varies from person to person, obviously, so there's no strict "minimum height".

There's three main groups of regularily available fret materials, nickel alloys, copper alloys and stainless steels.

The various bronzes are easier to obtain, have more options regarding the sizes and hardnesses and are easier to work with. Bronze wears faster than stainless steel, but for a normal player that shouldn't make too much difference.

The easiest way to tell what material the frets are made of is to ask from the manufacturer, or to post the make and model of the instrument, someone here most probably knows the fret-material for that exact make/model.

Regards
Sam