The total points you have are an accumulation of the points available for a reward. You keep your points as long as you keep your membership active from year to year.
Example: You earn in 8,250 in 2013 and do not use any rewards. Upon renewal in 2014, you camp enough to earn 16,100 points. Since your points from 2013 roll over to the next year, you have 24,350 total points towards a reward.