Another area of support is for your arms. Arm support, to me, is necessary. I'm actually surprised that they even sell office chairs without arms. One feature that you can find in some office chairs is adjustable arms. I don't really see the need unless you are going to share your chair with someone else that has a different body structure than you have. If you test out the chair and the arms are at a proper height for you, adding adjustable arms is worthless as far as I'm concerned.
Carla James Fabric Yogi