How long is a tire patch good for?

[LCHIEN]

another note on compact spares:
Since they're designed to last 50 miles, you don't want to drive 50 miles on it after getting a flat. Because it will be used up and you should really get another replacement for it at the same time you get your tire fixed.

What you want to do if you have to use the compact spare is drive 5, 10, or 20 miles to the nearest tire repair place and have your regular tire fixed or replaced. Then put your compact spare back in the trunk where it can be used again safely and still have 40 or 30 good safe miles on it. Make sure to air it back to the 50 or 60 PSI I think they want to have it inflated to.

[Black wallnut]

Tire patches if done correctly will last the life of the tire. Since you already believe the life to be nearly over it is also likely that a tire shop will not patch your tire. I've been there had that happen to me. Tire shops usually will not re-install a tire that is beyond the acceptable service life of the tire. rather than spend the money on new tires you might be able to find a good used one that almost matches the rest. However I'd think in terms of resale value. If your car is nice and newer than 10 years old you might break even in the selling if it has good tires, if it is an older beat up clunker then likely you will not.