If you purchased a membership directly with Starfall, your account does not renew automatically. You will receive a renewal email reminder within 30 days of your expiration date. If you choose to renew, you must do so manually at that time.
If you purchased a monthly subscription through Google Play or the Apple App Store, your subscription will renew automatically until you cancel. You can cancel your subscription through Settings on your device or through the store from which you purchased it. You must cancel your subscription at least 24 hours before the end of the current period to avoid an additional monthly charge.