I pump my 23mm and 25mm tires back up to 100lbs before every ride. They seem to always to have dropped to between 80-85 on my 2-3 weekly rides? I carry 2 tubes, 2 C02 cartridges, a Blackburn Wayside inflator, tire irons and a small multitool in a medium size seat bag. I wrap the tubes and C02 cartridges (separately) very tightly with cellophane (plastic wrap) to save space and help ensure that the tubes don't get damaged because they're no longer in a box. My bike(s) never leave home without the seat bag.