The mods here are pretty lenient about such things, as long as the information is "relevant" and / or "strongly pertient to the subject" and not some silly "Me too!" or "That's a good one!" remark. I think two months is a standard benchmark, but they're primarily interested in good info that justifies such an update.

I mean we've had 5 (yes five) year thread necroposts. I think the best I have seen but can't remember where it came from was seven years.