Usually I just change whenever the feeling strikes me and I feel like it's been long enough since I last changed that I'm not just changing willy-nilly. For instance, I switched from Dark Knight Cecil to Jubei just 'cause I was getting back into Onimusha and I wanted to reflect that somehow. I guess most of my avatars have been from Japanese video games? Well, actually, I used to have the mummy from Bubba Ho-Tep, so that's not even true.

I dunno, I just pick whatever seems cool at the moment.