How many years do Mason Jars last?

These need preserving!

Today is Canapalooza at The Hot Flash Homestead. The bulk tomatoes are long finished and put up for winter, but with a still-ongoing harvest, I also decided to put up another 60 pounds of fresh, new tomatoes in salsa and spaghetti sauce.  This last weekend I sent Big Ag out to buy some new mason jars, because I don't use mine for canning if they've seen three canning seasons, maximum.

The answer to the question of "why not?" is that horrible, sinking, panicked feeling you get when a full mason jar breaks in the canner and a quart of tomatoes goes floating around in the water you are trying to can in. Or when you lift a jar out and the bottom cracks open, splattering hot goods all over yourself.

The fact is, mason jars are one thing where the phrase, "they don't make them like they used to," is a valid one.  My really old mason jars, which are over 20 years old, are just fine and will probably last forever.  But the newer ones, the ones between 4 and 10 years of age, are unpredictable and have a shorter shelf life than I would have thought.

Voila!

For a long time, I blamed myself as the culprit in any jar-breaking accidents, since I am the usual first suspect when things go south in the kitchen (that assumption is usually correct, too). I figured that maybe I'd put the jars into the canner too cold, or with over-tightened lids -- you name it.  But as I became more and more careful and it still happened, I was forced to admit the jars I'd bought just three years ago had become structurally unstable, somehow.

Some of the problem may have been that I had been using my jars in between when they had canned goods in them.  I would fill them and stick them in the microwave when I wanted to heat water. I drank from them.  I stored leftovers in the refrigerator using them.  In short, once they've been used a couple of times, I tend to heat, dishwash, refrigerate, and even freeze those old glasses a lot, to a point where I think sometimes they just can't handle one more super-heating like the canner provides.

Best friend and occasional foe.

So every couple of years, I have now resorted to buying some new ones, since new jars have never broken in the canner -- one once.  I try and vary my stock so I know what year they are from (narrow mouths one year, tinted for a different year, wide mouth for yet another), in order to identify which ones should be put aside for one or two more canning seasons, and which ones need to become drinking glasses. 

How has your experience with mason jars been?  Have you ever broken one in the canner?