one of the strange things about the 15,000 mile for frequent flyer stuff is that it's made some short trips better values using frequent flyer miles than some long trips.

so when a flight costs $400, it can make more sense to use the 15,000 miles for a ticket to dc. (which american and united allows) than to sav use 25,000 miles for a trip to l.a. that would cost $250.