1. If it's a leak at the valve, I don't patch it.
2. If it's a blow-out (huge hole!) I don't patch it.
3. If it's slow-leak and I can't find the hole, I don't patch it.
4. If it's been patched 4 times (or more) already, I don't patch it.
Otherwise, yes, I patch tubes. I prefer Rema patchs but I find that any old rubber cement works just fine.
Rick / OCRR