reward expiration date change?

I've noticed that several of the rewards I would like to make use of have Jan. 1 expiration dates. Is this normal, do they automatically update the expiration dates at some time toward the end of the year, or have we just lost more useable rewards to the tightening of this site?
Thanks

Most rewards are to be used within 90 days of purchase, but some may have other expiration dates. Site tightening is probably why...I mean, they supposedly only make ONE MILLION dollars a day on MyVegas. :-)