I like to make about 20 band sets at a time. I usually carry 2 on me for back up and I like to make another 20 or so when I get down to 5 or 6 spares. I don’t love making bands so when I start making them, I try to keep going for a while.
None. I am learning what makes a good band-set and have not arrived at a preferred formula. So, each band-set is a reaction to the last band-set and I attempt to incorporate what worked and avoid what didn’t.
Plus one spare in each of six individual shooter cases I carry. Everything in red is my standard. The other colors each have something a little different inside. The one set of yellow bands are made for my nephew. Boy is seven and shot lights out with that stuff.
I'm tinkering with SS black right now so when I take a set off, I mark them as used and store them in a box with other band sets that I've tried. Also have a ten pack of precise yellow pre-mades from PP. All in all, I probs have 20 or so that I can use. I break very few 'cause I like a light draw.