What is easier, playing a guitar standing or sitting?
If you are a sit-down guitar player you should make an effort to practice playing standing up as well. Two good reasons for that: it will make it more difficult to look at the neck when you play and consequently you’ll learn the neck in a new way. Also if you’re ever called to play standing up you’ll have some experience at it, having practiced that way before your gig. I would guess though that a stand-up guitarist probably spends plenty of time playing seated anyway… so I guess I’d say it’s easier to play guitar standing or sitting if you have, in fact, practiced that way a bit. However you do it, don’t forget to have fun!