Many of my jars are old, name brand and going strong. I actually feel the older ones were stronger -- could be wrong. At this point, I'm still finding a doz here & there in going thru boxes. Pretty well stocked with bags for the vac sealers. Have plenty of pint jars -- best for me as only one in house. Lots of lids -- Some packed were Ball with $1.49 price tag, you know they were stored a while

but, just fine. I used to pick up jars at yard sales...those may happen again, one day. LOL
My grands used to put paraffin on their jellies. Seals were not "as" critical with that 2nd inside seal. Anyone out there do that now?
I see more interest in canning supplies, like garden seed but, no one is looking at buying 300, that I see. Many will go the freeze route as it is less investment up front...if they have a freezer. You have to consider that many people shop week to week, so a 6 month supply of canned goods at one time is not even on their radar. They have no idea how much food that amounts to. And, for many, 3 tomato plants are a big plan. Hey, I lose more than that to accident.
I have used and have in stock, WM lids. Mine have worked just fine so far. Most are Ball & Kerr. When I can the jars normally set on my table for about 2 weeks….then to shelves, where I check stores about once a week -- whenever I add more, at least. After 4-6 wks, I settle in to "ok".
The "PING" It's such a satisfying thing. Only "we" could understand!

All the time work & love that sums up!
PING!!!!!!