How do glueless patches last when they're NOT installed in a tire? Typically I'll patch when I get home, then roll the tube up and stuff it in my repair bag. I've had glueless patches get ripped off while bouncing around in the bag for the year I usually go between flats. I guess I could be careful to fold the tube so that the patch was protected by the rest of the tube, but that could get tricky by the time there are 3 or 4 patches on the tube.
The only way to get a glue patch off is to rip the tube.
Again, maybe I'm doing something wrong. But I prefer to use the patches that are so good that they simply can not be removed once properly applied; less to worry about.