I’ve had pretty good luck so far. Some cans I missed on rotation that were 6 years old. Still good. I have seen some swell in tomato sauce after 5 years.
6 months should be a safe rotation. 3 months better.
A year or so ago, I used a can of tomato sauce that was about 5 years old.
There was a noticeable “shrinkage” of the product, it was about 3/4 of an inch down from the rim. I take that to mean that even in professionally canned products, they cannot practically seal it against a bit of water loss.
Results?
Smelled fine, cooked up fine, angel hair pasta and garlic bread, some olives, it was a feast!
I was always under the impression that tomato products were, in general, too acid to have botulism.
But acidity by itself is not enough of an indicator. I had a can of mandarin oranges start to swell, so those got pitched.
Of course not all food contamination is necessarily botulism.