Sometimes.. Depends really on how I feel. Sometimes I feel like my art isn't good enough to be submit so, I wont. Then, sometimes I will post a few things during the day when Im in a good mood. ^^ Really depends on my mood.
Lately I have, and I've been feeling a little guilty because I haven't submited in so long! (But I'm so busy with school >< But usually I think you should just submit whenever you have art... and shouldn't feel pressured by others. Art is something you make on your own time when you are in the mood, inspired, etc. Otherwise, its usually something that isn't your best work.
Sometimes I do feel obliged and that is weird. I put it down to watchers being so picky to what they will and wont comment on. Seriously I believe half of mine are only waiting for my next simpsons/zelda parody and aren't really interested in anything else I create. It's sad, but well, lately I've been doing my own thing regardless