If you properly clean the tube, and use a Rema patch kit, the patch isn't ever going to come off or leak.
I use a can of Rema BL-8 for Road Tubeless patching but it's also good for tubes.
Here's a tube I patched; bottom patch is a standard Rema patch from the bike patch kit. Top patch is a Park patch put on with the blue Rema BL-8 vulcanizing fluid. You can see that both of them are practically welded to the tube, never to come off.
