On the plus side - if prices drop you can get a credit for the difference to be used toward a future JB flight.
**Keep track of the cost of both the departure and return flights separately - if one drops and the other goes up so your overall rt fare stays the same or rises, you can still get a credit for the difference in the flight where the fare dropped.
If the fares go down do you just call Jet Blue for a credit?
I won't fly anything else if I can help it.