Most if not all airlines offer a full refund if a purchased ticket is cancelled within 24 hours (actually, midnight the following day), so it only makes sense to check and rebook if the price drops or if other changes are desired before then. However, once "locked in," I've seldom revisited except for possibly changing seat assignments. At least on Delta, flight change fees are certainly way more than any fare reductions; and besides, who needs buyer's remorse? (Yes, Southwest is much better in that regard.) Nonetheless, and mainly for future reference, I recently started checking to see how prices change as departure draws nearer. Fortunately, no buyer's remorse this time, as my fare increased right after booking last week. And while I've heard that the fare "sweet spot" is 54 days prior to departure, I've seen far too many exceptions to necessarily agree. As long as my dates are flexible, I've found it often pays to play the "wait and see game" unless something really attractive shows up within 3-4 weeks. It's "amusing" to watch fares for different flights even for the same day bounce around, while that that little "only 1 or 2 left at this price" notice seems to mean absolutely nothing! Anyway, I'm just curious who else watches fares after booking, especially when it's impractical to make changes.