I've a tool roll with a 15mm short wrench, no glue patches, 4,5 and 6mm Allens, couple of tire irons, screwdriver Lezyne pump and a scrap of paperish shop towel. I use a bag and include some regular kitchen paper towels in case the porta potti or underbridge doesn't have toilet paper. Sometimes a produce bag from grocery store to protect my leather saddle. If I'm going to leave my bike a cable lock. A water bottle is a good idea. I like to take my Brompton to other towns to visit family and the tool roll is good for repairs. I favor fairly large bags that will hold the tool roll, wallet, phone and a sweater or a jacket as the temps can change a lot on a ride. Since I'm riding for exercise and pleasure a little extra weight is easily offset by comfort and convenience.