Quote Originally Posted by Oglethorpe View Post
Individual thickness of each hair. Maybe I'm "splitting hairs" but a blonde hair, blue eyes, fair skinned guy is going to have thinner, more pliable whiskers than a Sicilian with olive complexion and black hair.

In other words, you can't place the responsibility of the durability of an edge on prep alone (and perhaps I have gone slightly off-topic as a result since we are talking about prep only).
An absolute measure of prep (or an absolute time limit on edges) is not going to work for the reasons you mention, for sure. But relative prep should be OK, as in "an amount of prep that adequately softens the beard of an individual". In addition, this is all relative - extending the life of the edge on an individual basis. So you might get 2 months from an edge based on your beard type with minor prep, while someone else gets 4 based on theirs, ceteris paribus. We want to know what happens to each person's edges if they use better prep - the first guy may extend to 4 months, the second to 6.

James.