If you're looking to cash in reward points for a vacation destination this year, you'd better be booking soon. Changes are in the works that you're probably not going to like.It has become a rite of passage about this time every year: Hotel chains that offer reward points change the rules.But this year, travel experts say, the changes are unprecedented."Almost every single hotel chain has jacked up, extraordinarily, the amounts of points that you need for a free night," says Brian Kelly of ThePointsGuy.com."Extraordinarily" as in doubling the number of points needed for a free night's stay.Some chains, like Hilton, are starting the changes at the end of this month.Kelly says that might prove to be too much for otherwise loyal customers."I think once people start seeing that these points that they accrued for years are now worth about half as much, I think they're going to start losing customers," he predicts. The changes at Wyndham have already taken effect, with many of its hotels actually requiring fewer points for a free stay, although nearly a fourth will require more.Marriot and some others are just introducing more expensive tiers. Going forward, Kelly advises your membership in reward programs should be as diversified as your retirement portfolio.