It also depends on the patch. I keep one of those patch kits where you pull an impregnated gauze/rope through the hole in my car. This is a FAR better patch then any one of those temporary goop/gunk/slime ones that are injected through the valve stem, which are only temporary. The impregnated rope ones are actually very good, and unless you plan on being aggressive on them, on sustained high speeds, will be a permanent patch. I would use that if I were ever stranded on the side of the road.
However, if I have the opportunity, I would get the patches that must be installed with the tire dismounted, that has a backing patch, that has a stem that goes through the hole, and is then trimmed. Those are very high quality patches, and unless you're talking serious conditions, which by then you'd probably be looking at dedicated race rubber anyways, are very much a permanent patch.