Maybe I just have 9 lives, but in general I would say luck has been with me with most of the airlines especially if elite using expired upgrades. Especially if the cert just expired. I think my record is using and upgrade expired about 5 years. I never throw away airline upgrade coupons. A few years ago though a friend told me that she tried to use an expired upgrade, and they wripped it up. I believe that was UA in SFO.