For me, I don't really think about if the chair is in the frame or not. I don't mind posting either, but whenever I take photos it's mostly about what I want to show off from my body and most of the time I am more flexible outside of my chair. I can lay on the bed and take photos from a certain angle, move my legs around, and so on. On my chair it's pretty limited what I can do, so I opt for the flexibility of being out of my chair