One of the benefits one gets for being an elite member of United's Mileage Plus program is the ability to upgrade into the next class of service on select fares (most domestic fares qualify and some international fares qualify). Theoretically, there's also a benefit to being at a higher level in the program as your upgrades should clear sooner:
Status Clears at General Member 24 hours before flight Premier Associate 36 hours before flight Premier 48 hours before flight Premier Executive 72 hours before flight Premier 1K 100 hours before flight Global Services 120 hours before flight
This used to work pretty much dependably until there were very limited seats left (the last one or two seats usually were left until boarding time).
However, this fall I've noticed that United has not been clearing upgrades, even when there are a multitude of seats available. For example, I'm on a flight tomorrow (in less than 24 hours) that has 8 of 12 seats still available for purchase but my (and presumably several other's) upgrade still hasn't cleared.
This has been pretty consistent on the last 8 or 10 flights I've been on, both domestic and international. It seems that the guys in "inventory control" (the part of United that makes the seats available for upgrade) has decided to not release any seats for upgrade until 10-12 hours before the flight.
This kind of makes the cool table of when things clear pretty useless and, to some extent, a bit of misleading marketing if not an outright lie.
Here's to hoping it's just a temporary glitch in their systems and things will get back to normal soon.