Rewards Points will only expire if an account is "inactive" for 6 consecutive months.
An inactive account is any account in which the player has not logged in or played any games (cash or free) in 6 consecutive months (explained in section 2.15 of the Terms and Conditions). Once the account is inactive for 6 consecutive months or 180 days, the Rewards Points balance on the "inactive" account will be forfeited.