Question : How long are most people's visits to Bangkok when they fly in from Dallas?
Answer : Of course you're not most people, but if you were, you'd stay roughly 13 days.
Question : Would you be willing to change your travel days if it saved you money?
Answer : For the month of February, the cheapest day to fly is Saturday. Flexibility is paramount when booking travel plans in order to keep costs down.
Question : How often are prices changing for this route?
Answer : Prices for DAL to BKK do change a lot more than the majority of routes. However, the sooner you book, the better price you tend to get.