What feature should a subscription service use when a customer transitions from a monthly to a quarterly plan to avoid double charging?

When a subscription service manages the transition of a customer from a monthly plan to a quarterly plan, using proration is essential to ensure fairness and avoid double charging. Proration allows for the adjustment of charges based on the remaining time in the customer's current billing cycle.

This means that when a customer switches from a monthly to a quarterly plan, the system calculates how many days are left in the current monthly cycle and applies that amount as a credit toward the new quarterly plan. As a result, the customer only pays for the time they have left on their current plan, avoiding any overlapping or double charges for the same service period.

In contrast, trial options might delay billing rather than aid in the transition itself. Up-sell offers pertain more to encouraging a customer to purchase additional services rather than managing plan transitions. Advanced billing typically involves charging customers further in advance rather than addressing the immediate concern of switching plans and ensuring accurate charges based on the subscription cycle.