I patch my tubes, but usually replace them when I replace a tire; but since using Specialize Turbo Armadillos for the last 2 3/4 years there has been no need for patching.

I disagree with Kev's thoughts about glueless patches. I have used glueless patches for 6 years and never had a problem, one tube had as many as 13 glueless patches and they all held just fine with the Park brand. The secret to any patch job whether glue or glueless is to make sure the tube is sanded in an area a bit larger than the patch than, if using glue, spread the glue out larger than the patch and make sure the glue is tacky but not wet before appling the patch (the glue should change from a shiny look when you first put it on to a dull haze look then use a finger nail and touch an area that the patch will not contact and it should have a tacky feeling). I prefer the glueless patches now because there is no glue tube to dry out on you, the patch is actually a bit thinner, and it's quicker to fix a flat since there is no glueing and no waiting for the glue to dry.

I also aways patch on the road if possible before using a spare tube because I can fix the tube as fast as replacing it if I know where the leak is and I don't have to compact the tube down (get all the air out) to stuff it back into the seat bag. Fixing a flat can be fast if you know where the leak is just remove one side of the tire from the rim about halfway, pull the tube out just enough to expose the puncture, roughen then apply patch and stuff back in. If you don't know where the leak is just fill the tire with air and you can usually find it, if not then you may have to remove the tube entirely. At this point you have two choices, replace the tube. or pump air into the tube and try finding the leak.

Don't forget after you fix the flat and before you reinstall everything to run your hand inside around that section of the tire and check for foreign objects, and if you know where the hole is in the tire make sure the object is not still stuck in the tire.