How durable/reliable is a patched tube compared to a non repaired tube, assuming a quality repair was done.

They are stronger.

I kind of stink at repairing tubes, so mine generally leak the first time I refill them. But as stated above, a tube repaired correctly can last as long - or longer - than a non-repaired one.

Sweet. No worries then, the patched spare will be stating in place.

I think it really depends on the type of patches used, and how well you are at the repair. I recently repaired a flat I got on my commute home one night with a genuine innovations patch kit and I was able to get another 200 miles on the repair before the tire went flat again. Air leaked from the patched area. Cleaned the area with isopropyl alcohol and roughed up and applied new patch, only got about 50 miles out of that patch before it slipped from over the hole. I definitely don't think all patches are created equal. And my skills probably aren't the best.

Over the years I have put many thousands of patches on tubes (tires in the '70s and '80s weren't as nice as they are now). Less than ten of those patches ever failed. I used to throw tubes out when I found myself needing to patch a new hole next to a patch, but flats don't happen that often anymore. Nowadays, after three or four patchings the tube is beginning to show its age and gets tossed.

I must admit I am amused by tire/tube manufacturers like Continental that recommend replacing the tube when the tire is replaced and other sources that insist a patched tube will fail. This is all nonsense and is very much like the attempt by helmet manufacturers a few years ago to convince people to replace their helmets annually.

And the old saw that the steel of a bicycle frame gets soft in 3 years.

I admit I change tubes after they have 10 patches. But that's just me.

A properly applied patch should never "slip". I suspect that the patches you use are using rubber cement and not vulcanizing fluid. Vulcanizing fluid isn't the same as rubber cement. I always use Rema TipTop patches. They aren't just pieces of rubber and a tube of rubber cement. The patches and the vulcanizing fluid are two parts of a system that are meant to be used together. The patches and fluid use chemistry to make new rubber at a molecular level. Once the bond is made the patch becomes part of the tube and can't be physically separated from the tube.

That said, the single most important step to do with the Remas is to wait. You can't wait too long. I've let them sit for weeks (forgot about the patch job) and it made a good bond.

I don't think I've ridden a tube with more than eight patches. Something else goes wrong before I get to the ninth.

I know I'm not supposed to, but I use rubber cement when I patch at home, because it's cheap, and I like to avoid opening a tube of the fluid, since it dries soon thereafter. I carry the little tubes on the bike. Anyway, my patches with rubber cement have succeeded. Maybe I'm just lucky.

5000 miles on a tube with 3 patches, tube is probably closer to 8000 miles.

I just recently tried the REMA patch kit after dealing with the cheap box store ones for years (BELL),
It's like a Ferrari vs YUGO! The Bell is like gluing a brick to your tube after using REMA's.

I didn't have the cheap ones fail (although they were in MB tires, not higher pressure "road" tires), although I've had some "installation fails" that I had to re-patch.

I bought the box of 100 REMS patches because I was so impressed with them.

I did patch a tube using the BELL rubber cement & REMA patch and it seemed to work OK. Not quite as nice as using the REMA fluid, but good enough not to worry about.
It was for a CL flipper, so if I can go a couple cents cheaper on a patch.....and use up my 6 tubes of BELL cement.

Weight weeenie!

A well installed patch will outlast the tube.

And I have seen tubes that were 50 years old, still holding air, and bearing patches from many adventures.

+1 to all the advice and wisdom above. The few times I've had problems with patches I've been either positive it was user error or strongly suspected so. I've re-used decades old tubes with patches on them and gotten many miles of life out of them. About the only time I give up on a tube is if a patch needs to be applied too near another patch or if there is a blow out or problem with the stem. FWIW, I've applied hundreds of patches.

+1

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No problem with holes close to patches. I have overlapped a patch over an older one with completely successful results. REMA patches are the way to go. I am still using the ones I bought 30 years ago without problems.

Tube in one of my wheels is one that suffered blow out when the sidewall of the old tire failed. It took four or five patches to fix that, but it's been working fine.

I'm cheap enough that I can squeeze snot of out Lincoln's nose, but I not that cheap

Patched spares should use traditional patches with glue.

The stick-on glueless patches will peel off a rolled-up tube in storage. Glueless are just fine freshly patched and put back in the tire. No longevity issues then.

+1 to the good advice above. I have never had a patched tube fail at the patch--BUT you must use good patches and vulcanizing fluid! I use Rema. The Park patches that just stick on are total junk.

I got a road bike this year and found that at 110 PSI, my previous patching method was not working. I had never had a patch fail before, but I've had 3 of them fail this year.

My problem is that I didn't let the glue dry well enough first, and it's also possible that the patches I was using (from Harbor Freight) aren't up to that pressure. I'm now using some proper round patches (100 pack of Sunlites from Amazon), and I let the glue dry for a full half hour before applying the patch, and that seems to hold up.

The patches are quite strong though - even the ones that failed I was unable to remove without destroying the tube. What was happening was that the pressure would force a tiny bubble into the puncture area under the patch, then the rolling action of the tire would kneed that bubble, forcing it in the direction of travel, causing a needle-sized tunnel to form to the edge of the patch. It doesn't seem to be happening since I changed to letting the glue dry 30 minutes instead of 5.

Maybe this is a good place to ask a question. I patched a tube on the rim side, which failed. I think there was a problem with the rim tape, and it was rubbed by a spoke, and developed a little bubble that leaked. I put another patch on it, partially covering the first one. When I inflate the tube, it's sort of deformed. Since the area around the double patch isn't as stretchy, that part is sort of constricted, and narrower than the rest. Should I use the tube? Right now it's just hanging around as a spare, but I'm wondering if I should just chuck it.

Yup, I use the Rema tiptop patches, never tried any other kind or brand. So far so good on the repair!

they's not supposed to be a difference but I relegate patched tubes and patched tubulars to spare.

I just leave'em in, keep patching'em. I wind up tearing the valve or something before I run out of places to patch.

Tires on the other hand seem to reach a breakpoint where even if they look fine, they start getting more punctures, and those I replace.