In Appstle Loyalty, rewards do not have an expiry date. You, as the merchant, are able to disable the rewards at any time by toggling OFF the various reward rules you offer in your dashboard.
Once disabled, customers will not be able to see these reward rules in the loyalty widget in your store anymore. For codes, however, if your customers have copied one for later use, it is possible to use them at checkout even if the corresponding reward has been disabled; they simply won't be able to redeem further discount codes afterwards.
If you do not wish for this to happen, however, and want to refund unused rewards and give points back to your customers, go to the Customers section, click the View action, and in the Rewards tab, click to Cancel Rewards.
Currently, points in Appstle Loyalty do not expire.