With rolling billing, storage is charged each day based on the space you actually occupy that day, rather than a fixed monthly rental. For example, if you have 2 pallets in the warehouse today you are billed for 2 pallets; if one ships out tomorrow, you are billed for 1. This model relies on a solid warehouse management system (WMS) to track daily usage, and it is common among 3PL providers with good IT support. It means you only pay for what you use, which is more cost-effective for businesses with changing inventory levels.