What is the maximum number of pucture repairs an inner tube can take?
I would carry at least one unpatched, pristine tube as a spare.  Put the patched ones on the bike or keep for repairs at home.  The idea being that when you need it -- in the middle of nowhere, in the dark and pouring rain -- you're guaranteed that the old patches aren't peeling off or weakened and the tube should "just work".  Then swap it for a patched tube when you get home if you like.