I bought all my lams for many hears, but I'm able to grind my own lams for glass bows, trilams, backed bows, backings and such and wished I had the capability years prior.
This weekend was a good 'for instance'... grinding various lams at various tapers, for different kinds of bows, virtually upon whims. Grab a piece of wood, cut, grind, done in minutes... not waiting weeks or months. And suppliers don't always have what I want.
It's not about cost for me cuz I won't recoup any costs on any of my equipment since I don't sell them. It's just that I want to do it myself if I can.