Lengthen the guarantee window and say so

When to use it

When the current guarantee is short (14-30 days) and refund rates are already low.

How to run it

Extend the guarantee to 90 days or a full year, and make the longer window the headline of the guarantee block.

Why it works

Remove the cost of being wrong

A longer window signals confidence, and it gets used less because the rush to evaluate and return goes away. QuickSprout documents a product whose conversion rate doubled when a 90-day guarantee was extended to a full year.

Source: QuickSprout guarantee comparison