I've always kept a close watch on my upgrade balance in the past, but since United's unlimited domestic upgrade (UDU) program started earlier this year, I have not had the need to use any of my banked upgrade instruments.
I was thinking about that this morning and decided to check my balance. To my dismay, one of my systemwide upgrades expired last month. And I had no idea...
I've got loads of systemwide and regional upgrades and my next systemwide upgrade expires next month. I have no use for it, so I plan to gift it to someone at IAD next week on the way back from my trip to Montreal (unless one of you can suggest a better use).
Learn from my mistake: keep track of your upgrade balance. I'm not feeling too bad because my only travel last month was on Continental, but I could have given it to someone else.