Use it or lose it. That appears to be one of the messages from several upcoming Air Miles Reward Program changes.

Air Miles has announced that beginning Dec. 31, all Air Miles reward miles will be given a date-stamp of five years to be used.

This means that all reward miles accumulated on, or before, Dec. 31, 2011 will have to be redeemed by Dec. 31, 2016.

Any Air Miles accumulated after this date will have five-years to be used from the date they are earned.

Air Miles says the changes are to encourage people to become more involved in the loyalty program, noting some people have not redeemed any points in more than 20 years.

The average accumulation time is about two-and-half-years, according to the company.

Air Miles has also introduced an instant redemption program, meaning once you have 95 points you can instantly get a ten dollar refund at participating retailers. This program is set to begin in March, 2012.

There are ten million of the blue-and-white Air Miles cards now in use around Canada.