I started with a belt pouch, then in the last year switched to a chest pouch.
I found that when I had a 2nd AC, lots of the stuff I had in the belt, (tape, soft tape, marks) the 2nd would have with them. I also found that it was getting heavier with more gear, and then I had to tighten the belt which would start to hurt my hips.
The chest pouch got me down to the essentials. I currently have the basic Setwear one, I want to swap to the Conterra one when this one dies. But I have got in it; a sharpie, dry erase marker, black and white china pencils, pen, flashlight, multitool, and my Leica rangefinder. Much more comfortable to have than in the belt pouch.