I've never had a permanent patch fail.
But I don't use them on the road.
I do it at home in the garage where I have the time & tools & bench to do it right.

It seems to me, and I say this with literally no experience what so ever, that the most reasonable thing to do in terms of optimizing speed and cost would be to carry a spare tube when you ride and to just swap tires when you get a flat. Then once you return home, patch up the tube that was punctured and either keep it with you as your new spare and alternate between the two with every subsequent flat or swap tubes out again and return the fresh tube to your spares supply.

Most of the time I'm riding a bike with tires at 100 psi or more. Consequently, these are the tubes I patch most often and the high PSI is not a problem. Could it be the type of patch you're using? I've had good luck with the Remi Tip Tops mentioned earlier in the thread but I've used other types of patches with success as well.

I think that's what most of us in the "patch" camp do. That's my impression from having read threads here for 5 years now.

Yes, except that I don't keep spare tubes for the kids' bikes. They never go far without one of us though and we're typically not in a hurry when they're with us. I'd just patch their tube if it came down to it. They've never flatted that I can remember though.

When there's more patches than tube....

Magical thinking. It's a new tube, it's better. Or laziness.

The more pressure you put in a tire, the better the patch is going to adhere. there's 1000 times more surface area pushing the patch hard up against the tube than there is the little hole trying to separate them.

I run 80 PSI and I've still never had a patch fail, after years of running up to 6 or 7 patches on a tube. I HAVE run 100 PSI at times.

My roadie has 140psi in its patched tubes. :speedy:

8 bars always....

The pressure has nothing to do with it. Do you let the glue dry long enough before putting on the patch? It needs to look dry before putting on the patch. Do you sand the surface of the tube where the patch is going to go. Do you touch the sanded area with your fingers and leave oil from your skin on the tube? Done correctly patches don't fail. They don't fail later either. They work in any weather.

It's kind of funny, some of the assumptions on here. I just said I tossed the old tubes these days - I've probably applied hundreds of patches 40 years ago and most of them held up as I recall. I've had a handful of flats the last few years, mostly on the kids' or wife's bikes. When I don't feel like patching I use a new tube - a couple of bucks, what's the issue? The old one I might patch later, might cut up if I want a strip for some reason. I don't think I've actually thrown one in the garbage in two years. If anyone wants to keep patching the same tube more power to them. To me, that's throwing good time and money after bad but like I said it's still just a couple of bucks.

I bring a spare tube with me, so I can replace it on the go if necessary. When I get home, I patch the one I just replaced, and it becomes my replacement to carry with me.

In my experience, glueless patches are a waste of time if you're running over 50 psi

Never tried a glueless patch, but the normal ones work forever, if they're done right. I keep patching until the valve stem fails.