you didn't file or there is evidence of serious fraud etc. So, if you do due dililgence and don't have some scam going then yeah, holding on to that long is being super safe.

More likely, if there's an honest error on your taxes, they'll catch up with you in 2-3 years, and I know b/c I just spent the fall dealing with my 2016 taxes. ( I "won" btw, even though I probably did owe some money but not nearly as much as they were suggesting but didn't have the manpower to pursue it when I sent in a lot of support information. hell, they could have "accepted" my cover letter and I would have paid $751)

So yeah, I grind up my eight year old tax returns. (and 7 years doesn't take up that much space) on the other hand I was real glad I had good records going back pretty far b/c some it involved pre-tax and post-tax money, and I could show some post-tax basis from 2011, so yeah, it did matter I had my tax returns from 2011.
[Post edited by `lag at 03/17/2019 12:07PM]