Originally Posted by Pyrite
Thank you for the advice. Doing the calculations, I decided it is much wiser to stay overnight near the airport rather than get up at 2:30 and drive.
Seems like a wise move. As others have said, IAD is unpredictable, partially due to logistics that are more complex than at other airports (security line configuration, moon buggies, the whole parking garage game). Anything you can do to remove nodes (and hence uncertainty) in going from your house to IAD is a bonus.
gvdIAD's idea of parlaying a few days of free parking from the hotel is a good one