Eh, idk. Depends on the person. I've been going for a "scruff" look for a few years now. I trim close-ish 1-2 times/week, just before it starts to get itchy from hairs getting long enough. I always have at least 1-2mm facial hair.
If I go clean-shaven, I have baby face and I look 10 years younger. Not a good look. A bit of scruff makes me look closer to my age, but I don't like the look of a full beard on me since I can't grow a decent mustache. It looks like I'm trying too hard.