I wrap a couple yards of Duct tape around a old Rx bottle and throw it in my bag. What's inside the bottle? It's a mystery, could be ear plugs, or aspirin or paper clips and safety pins. I made a quick fix kit for my truck out of a length of ABS pipe. I wrapped at least 12 yards around that.
Truth be told I sort of out-grew Duct tape when I learned about Gaffers' tape. Don't get me wrong I still use Duct tape, just not as often.