Size matters. An arm chair caddy might have two or more sections. Sure, you could get one with eight sections and bulk it up with everything but the kitchen sink. But the advice here is to use the arm chair caddy for essentials only.
If you need more room for keeping a beverage, keys or something else, caddies with a tray on top are available. Some caddies without a tray can also hold a cup. With a tray, you can even keep a pad by your side for writing notes or a letter.