I'm particular and irrational, if it has no AF and it's easy for me to keep open I don't see any reason to close an old card. I'm basically keeping 3ish (the second Amex doesn't really count) to anchor my report for the future short of filing BK in which case of course I have to start over again:
BOFA: oldest, I just need to occasionally drop something on it
Secured DCU: it's secured, $500, DCU isn't ever going to close that they will keep the depositary bribe.
Zync: $10 recurring and a $25 AF, it isn't going anywhere either.
Amex BCE: backdated to being my second oldest card when Amex was still doing that, the Zync activity will keep it open.
Rationally? I know, *know* I don't need an 820 FICO 8 score for anything relevant now and probably not for the future and when I was able to establish that even with a 9 year old card, 4 years AAOA or so, and a cleanish file (CFA still depressing some models) and I was well over 760 on the mortgage trifecta too, WGAF about closing an old card when by the time it's aged off I'll have another 9+ year old tradeline?