Every couple of months. Partially out of boredom, partially because people keep bloody stealing them. I kept having people take the exact same picture, even ones I had specifically made it seemed.
I liked my 'Legion' from Mass effect 2 avatar, but I assumed people would think it's the reason for my name change and title, which it wasn't supposed to be.
Thanks to the title and name though, I imagine people will be able to recognise me regardless of my avatar now though. Actually, considering the seemingly short average attention span on here, I won't hold my breath.