Originally Posted by
safigan
I always check the price of a round trip flight against 2 one-ways. Often it's a bit more expensive to do 2 one-ways. On my international business class flights, it's often a LOT more. On those occasions, I look at Skymiles as they often don't carry the large one-way premium. YMMV
At least flying out of BOS, I book as two one way trips since it is always the same as a round trip. Maybe ATL has a 'penalty' but I thought that at this point all domestic flights are with one way routing rules, unless you found some strange exception.
International tpac/tatl yes book round trip or you get nailed on price.
Caribbean I still see most one way trips as having no penalty vs round trip.