I carry a spare tube, and also a Rema patch kit. Never had more than one flat at a time, but friends have. Also-before you put in a new tube, run something (not fingers) like a tissue, handkerchief, something that will snag anything left in the tire. Patch the punctured tube when you get home-take your time, do it right, too easy to be in a rush if done while on a ride, and do a poor job.