With reusing old lids for canning, I always recommend to put each jar upside down right after it was tight.
Let it stay for a while than you’ll see if it’s closed properly.
Sometimes it may happen you’ll see foam on one side. That means the lid was not good and it won’t preserve your canned vegetables.
If this happened, you can re-boil (re-sterilize) an affected jar with a new lid and repeat this again (put it upside down for a while).
Or just keep in refrigerator and use within a week.
If this issue may worry you, just avoid reusing old lids. Buy new ones.
If you are new to canning, I would recommend you to buy a complete guide to safe canning:
Ball Complete Book of Home Preserving