I feel mine looks best after a couple months. They're a tad too dense new, even at 90%. The only time I wear them out prematurely is if I scratch a certain area, repeatedly, with my fingernails.
Many people on here are on a mission to make a system last as long as possile....like a year.. and quite honestly they look awful when they do.
I've fallen victim trying to reach 3 months when I started wearing. When I finally replaced the system( which I thought looked good) I looked at a few pictures of the previous system on its last leg...and I couldn't believe I was walking around that way. Seeing it every day.. you get numb to the bald spots and the sparse hairline, that comes with age....
3 months is a safe bet...Unless you see a specific reason to change sooner.