Originally Posted by
augias84
If your travel plans aren't flexible, then buying early is usually the best deal.
This is not true. The best time to buy a flight changes, but is generally somewhere between 100 days and 3 weeks before departure. UA (and other airlines) often don't open discount inventory until they see how sales trends look.
There's no hard and fast rule for the best time to buy airfare; if there were, the airlines would adjust their sales practices to eliminate it.
Originally Posted by
augias84
Looking at flight status of the same flight over the next days (like, 3 days out) can give you an idea of how full they get -- if they're basically full a few days out, your chances of upgrading might be quite small.
This tells you little, for a number of reasons; seasonality and day of week are highly impactful on your upgrade chances -- and there's no way to distinguish between a flight that's full of upgraders and a flight that's full of paid passengers. They both just look full.
What you can do is to use the inventory information that UA makes available; look at expert mode (just for SFO-NRT, LAX-NRT, etc., not for PHX-NRT) and check the inventory buckets. PZ > 0 is needed to upgrade. However, if PZ=0, you want the flight with the inventory that's "closest." The bucket order is J JN C D Z ZN P PN PZ IN I. If you can't find PZ > 0, and you're intent upon waitlisting, look for PN > 0. If no PN > 0, look for P > 0, etc. The further away from PZ you get, the fewer discount tickets UA is selling. Having discount tickets available for sale is a positive indicator that upgrade space may come. (The converse is not necessarily true for a flight this far in the future; UA has started treating J inventory the same way it treats Y inventory, holding prices high far in advance to see if they get any takers).
Originally Posted by
augias84
already you're throwing money out the window by booking a W fare!
Not in this case. W is the lowest fare class published in the PHX-TYO market -- and even that requires a two-week stay that the OP likely doesn't have, since the original discussion was about Q and V fares. Fares in and out of Tokyo are much higher than much of the rest of Asia.