For SWA, you will probably want to get them as soon at they are out. But if you don't mind taking your chances, you might wait for a fare sale for those dates, as mid-January is not all that popular a time to fly (tho with ppl figuring out that they have time off for MLK Day, that might begin to change - MLK weekend is our fav time to fly south from New England).
We are still waiting to buy tix for our January trip to VB (via BWV for one night - gotta love those APs with DVC). I had been following Delta/Song's fares since we started planning, and they were standing at around their regular levels for some time, then JetBlue came out with the January schedule and they dropped to meet those. Maybe when SWA comes out with their fares, they might drop again. We are strongly leaning toward JetBlue this to try them out, even tho we have been Delta frequent flyers since the 80s, and have two other trips already booked on Delta/Song.