I always book a BB for a date that I generally can take a trip. There is no harm, no foul if I decide to cancel it, but if it is not booked, it is off the table once I am home. One of the things to rememebr about discounts is that they are never guaranteed, and you never know what willl be offered if there are any. I prefer to know I have something in place, and if something better comes up can be changed, than looking at what I passed up and then being unable to find something to mitigate the cost of a trip.