I've had decent luck with glueless patches on low pressure tires (less that 70 PSI or so) but not on road tires (100 PSI +). I always carry a spare tube (a couple on longer rides) and a new patch kit. I've only need to patch on the road once so far (3 flats on one ride) and swapped the tube of cement out with an unopened one when I got home. Opened tube of cement when into the home patching kit that gets used for the majority of patching so is used up before drying up.