Do many people do this? I keep one or two spare tubes, levers and a pump with me, if I get a flat I change the tube, look for whatever sharp may be in the tire and take the flat tube home and patch it there?

This has worked for me for years. On the really long odds of getting two flats in one ride I now carry two tubes now, I didn't use to, but was never caught without a tube when I needed one.

No flats last year, like 1 or 2 the year before.

I don't feel comfortable putting on a patch out in the wild when I don't have all my tools near me, and I want to get back on the road as soon as possible. I can swap a tube out in just a few minutes.