Reward points have a validity of 12 months. If you have not made an eligible stay within the past 12 months, your Rewards points balance will be reset. Essentially as long as you stay once a year and earn Rewards points for your stay, your Rewards points will never expire!
Status points, however, do expire at the end of every calendar year, on 31 December. Status points accumulate based on stays over a calendar year and are reset on 1 January each year.
You can check your Rewards and Status point balances either on accorplus.com or the Accor All app.