I do reuse lids for freezer jam, but never for processed canning.

I canned for years and years and NEVER would reuse the flats. Rings and jars yes. Too much chance of botulisim in reusing the flats. I have reused the flats with rings and jars to store beans, rice, etc in the pantry but never in canning.

I never have, but I thought they wouldn't seal after the first time? I don't know.

WOw .. green beans from years ago ?? Whoa .. we always tossed out something after a year,but then most times it never lasted the winter around our house !LOL We use new lids, we will reuse the rings if there is no rust etc.. but usually when you get new jars, new rings & lids go with them . What I never had luck with was reusing mayo jars, for some reason they burst in the water bath. The pint dressing & mayo glass jars, DH's Grandmother would use for jelly and that is a practice I have followed.

Nuh-uh, I would never reuse the lids. The rings, yes, but not the lids that seal the canned goods. It's a lot of work to can and I don't like doing things over. The rings aren't that expensive when bought by themselves and worth the price to not have anythiing go wrong or anyone get sick. I'll save money elsewhere, but not on canning lids.

I only make fruit jams, and I use the inversion method to seal them (pour screaming hot jam into hot, sterilized jars, whack on the lid and screw it down tight, invert the (painfully hot ouch ouch) jar for five minutes, turn right side up and wait to hear the lid go "ping!" as it cools and the contents contract). This method used to be described on the jam instructions in the pectin box, but now is not there - presumably because somebody decided it isn't safe. I have used it for years, frequently with re-used lids, and have NEVER had a seal fail. I would only try this with something that is entering the jar at a crazy hot temperature, that has a high sugar content (inhibits growth of yuckies) and which I will be able to hear go "ping!". Since I don't can I don't know if any of that applies to other stuff.
Alison

I was always taught to use new flats. I do wash the old flat and put back on the jar just to keep the dust out. I rewash the jar before using. It has been years since i did any canning.

I use new lids. If you are going to the trouble to can it and can afford to, it is worth the new lid.

I would NEVER reuse a lid. I'm afraid I would not get a proper seal and I would loose what was in the jar. Too much HARD work to loose any of it.

I always use new lids for canning things I am going to store. I do not want to take the chance that it might not seal. I do reuse the lids for things like storing dry items on my shelves or in the refrigerator.