If they are in perfect shape I will re-use them. Never had a problem with them. I've had more new ones not seal than used ones.

I have on occasion reused lids for jelly. There were usually a few that did not "pop" so those were used first or given to friends for immediate use only.
If you are planning on long term storage (more than a month or so) I would make very sure the seal was secure.

Just because they "look good " is not what matters. How the pressure treated the rubber in the canning process is the important factor....i would always ....Always use new lids please.

I have been canning now for 40 years and I always use new lids but I reuse the rims. I figure the lids can be bought without the rims for a couple of dollars. So a couple of dollars is worth it. Just to have the peace of mind that my canned food will be safe to eat.

No, I would never reuse the lids for canning & "hope" they will seal. However, I do reuse the "good" ones for general storage of leftovers such as soup, etc.

There are now reusable lids!
 

The Tattler lids advertised on Glenn Beck's show are reusable and guaranteed for a lifetime. They are not plastic, have no PBA and have been tested up to 50 times I believe with success. Just google Tattler reusable lids and you should find them. Worth the extra price if they last forever!

I reuse the rings and buy new lids.

I only use used lids on jellies. On everything else - news ones.

I use new lids-always! I do re-use rings and jars though. New lids are a small price to pay for peace of mind. And too much effort and $$ goes into it all to risk it!!