Your Mode Points are always safe in your account, and there's no rush to use them. There's no time limit for redeeming your points.
It's a good idea to set a goal for the Gift Card or physical item you want. Once you've saved up enough points, go ahead and redeem them for your chosen reward. After that, you can set a new goal for another Gift Card or physical item. This way, you can keep earning and getting rewards at your own pace.