Whether it's Duct, Gaff, Packing, Electrical, Masking, Painter's, or any other tape roll under the sun, the easiest way to keep them is on a loop of rope with a clasp or carabiner on one end.
Just like using the right tool for the job, using the right tape is also essential. There are folks who are in the cult of duct tape, but frankly, it's comparatively expensive and in many cases there's a tape that can do a better job. Keep them all together in the way I've shown, and get familiar with which one is right for the job.
I learned this little trick when I worked briefly in film production. I didn't see it being used anywhere outside that field, until I met my classmate Luis Violante. I asked him where he learned to do that and he said "oh...when I worked in production." Go figure.