Originally Posted by
Medic Zero
+1 to all the advice and wisdom above. The few times I've had problems with patches I've been either positive it was user error or strongly suspected so. I've re-used decades old tubes with patches on them and gotten many miles of life out of them. About the only time I give up on a tube is if a patch needs to be applied too near another patch or if there is a blow out or problem with the stem. FWIW, I've applied hundreds of patches.
Tube in one of my wheels is one that suffered blow out when the sidewall of the old tire failed. It took four or five patches to fix that, but it's been working fine.