Not a stupid question by any means. I have done this before. Figuring you are computer literate, set up a few bookmarks for this. The cruise line site, the mega sites (Travelocity, Expedia, Orbitz, Hotwire) a couple of spider sites (TravelZoo, BookingWhiz) and some cruise specific sites (Cruise.com, CruiseComplete, Cruise411, etc). This should give you a heads up if there are changes. When I have decided on a cruise for a certain time and am flexible, there have been a lot of changes in rates both up and down, plus an opportunity for an upgrade. It is a very variable situation.