You pay when you upgrade from Basic to Premium or Teacher and when you renew one of these subscriptions. When you subscribe to Premium or Teacher on the web, we always bill you for the next 12 months. On the iOS app and on the Android app, we also offer both plans for 3 and 6 months. If you save your payment information when you purchase your subscription on the web, your Premium or Teacher subscription will automatically renew for another year. If you don't want automatic renewal, you can disable it in your subscription settings. When upgrading with payment methods that we cannot save, and with in-app purchases, there are no recurring debits. This means your subscription will simply expire without an active renewal (= downgrade to BASIC). No matter which payment method you choose, 5 days before expiration we will remind you by e-mail about your subscription status or upcoming debits.