Like other posters here have already said, I carry 2 tubes on me. I really don't like to patch a tire on the spot. I usually just cram the tube in my pack and fix it when I get to work, or home. Depending on when I think I may need it. It's a drag to try to patch a tube in the dark, or in the rain.

Much better just to pull the wheel, pop out the tube, sweep through the tire for what caused the flat, Put in the new tube and shoot it with a CO2 cartridge. I'm usually back on the road in 10minutes or so.

I have had great success with the "Slime-Scabs" patches. They are a step up from the usual cementless patches, and I put one in my kids rear tire more than a month ago, and it's still holding air. I also carry Park patches too, but I really like the slime ones.

Might I also suggest, carry a pair of nitrile surgical gloves with you too. Put those on your hands before you work on your bike. Especially if it's the rear and you are dealing with the dirty chain. They're lightweight, and you'll be glad you have them if you need them.