I will take out the punctured tube, try to find the cause, remove the cause, install a spare tube, and stuff the punctured one into the space I had the spare one. When I get home hang the punctured one over a nail, and grab another from the spares pile. When there are 2 or 3 that need patching, I get out the glue on patch kit, I pump them up, using a bucket of water I look for any holes, mark them with chalk and let the tube dry. When it's dry, I let the air out, put on any required patches, then let it sit until the next day. Pump it up, and do the water test again. If there are no leaks, I let the air out, roll them up, and put them at the bottom of the spares pile. They only get tossed if they can't be patched. If I replace a tire, I replace the tube and the old one goes on the nail to be checked.

IIRC out of 2 bikes and about 3 spares, so 7 tubes there are 2 that don't have patches on them, they all seem to work just as well as new ones. I think the last tube I bought cost $4, the last patch kit had 10 patches (and 2 glue tubes) for $2, so 20 cents per patch. I've found tubes on bike trails, from people who don't pack out their trash . I usually grab them, if they are the right size, and not obviously ruined, I'll keep them, if they are not, or the wrong size, then I will toss them in the next rubbish receptacle I come across. I was once riding with someone, and came across a tube, looked to be in reasonable shape, wasn't the right size for me, but it was for him, he got a $15 tube for 20 cents.