Usually I cary 2 CO2, one CO2 nozzle, a spare tube, a patch kit (although I've never had much luck with patches so I've no idea why I even bother), two tire levers, a multitool, my ID, a credit card, and about $20 to $40 or so in cash. I have a very minimal saddle bag (Lezyne Road Caddy) that amazingly holds it all. Then my phone and a cliff bar or some other food goes in my jersey along with my car/house keys.
I also bought one of those Waterfield Design Cycling Pouches that holds everyithing mentioned above (except for the food) if I just want to keep everything in my jersey and go without a saddle bag. On 50+ mile rides, I may bring both so I have two tubes and 4 CO2 cartridges etc.
Then a water bottle or two of course.
Last edited by Gus90; 08-09-15 at 06:31 PM.