Many office chairs are adjustable. You can change the chair height and move the arms, and some office chairs even have adjustable lumbar support. So before tossing out your current chair, make sure you're sitting in an optimal posture for your comfort by trying out different ergonomic positions. I cover ergonomics above. Allread, the expert I spoke with, had two main suggestions: You want your back to touch the back of the chair. You want your feet to touch the floor (or you should use a box or footrest to prop up your feet). Allread also suggested rolling up a towel to use for lower back support if your chair doesn't have lumbar support.