I usually just let it grow if I'm not going out anywhere, then shave it a lot once I have like college to go to or friends to see. I have quite the baby face so facial hair looks ridiculous on me, I only leave it unshaved due to being a lazy bastard.
I just let it grow, then shave it all off once it starts to bother me. Usually I'm fine with about a 2 months worth of growth on my face. I've gone up to 6 months, but then it got really itchy and hard to maintain. :/
Argh, beards....its not that I hate them, is just that mine tends to become noticeable every single day. I like having my face without facial hair, but my genes say otherwise. However, if I'm living my rare but short bursts of hikikomori life, then I don't mind facial hair at all unless it starts to itch, but I tend to hate it when going outside.