Whats the longest expiry date you've tried?

[JustMe]

Couple of months ago I went to make a tuna sandwich. Can of tuna was dated 2009, jar of mayo was 1 year past date. The tuna was fine, but the mayo had a weird almost tinny taste and that was tossed..

I then started checking other stuff in the pantry and found much of the dairy based things like mayo, tartar sauce, etc had darkened so those were all tossed as well. I'm thinking 6 months past date is a good limit on those