I would do a run to keep my status (last year visited Atlanta from New York for a day just before New Years for that reason) or to visit a place I wouldn't normally go for the miles.

The place visit would usually be in conjunction with some bonus miles, like the 200% one available now, so next month we will spend the holiday weekend in Rio. Is it a pure mileage run, probably not because it's part vacation, but we certainly wouldn't be going if there were not the bonus miles.

I've also done some of the old days qualifying flights, take a flight out of White Plains in February and get double miles for the rest of the year type of thing.

I do it for status, and for the miles.