Some inventory changes daily, but depending on your location and dates things may or may not change often. The problem is it often changes in the wrong direction!! They sell available rooms or the price goes up for the same hotel on a given day. It depends on the hotel when they release inventory to Priceline/Hotwire... but often you will see new options appear at 90 and 60 days out (probably 30 days out also but I don't usually wait that long to book). If you can't find what you are looking for on Hotwire you might make a back up reservation and then wait until 60 days out and see what happens (by the way....that is 60 days out from your last night, not your first)
I do not have good luck getting low rates at the last minute on Hotwire....others may disagree and have had better experiences there, but it seems to me the longer I wait on Hotwire the higher the price. Priceline seems to do much better for last minute bookings.