Walrus's leasing storage model is indeed interesting — users purchase fixed-term storage permissions using WAL tokens, covering up to approximately two years. This design avoids the "data garbage" problem common in traditional permanent storage models.

What's more flexible is the support for smart contract automatic renewal functionality. This means you can set a storage period, and upon expiration, the contract automatically determines whether to continue storing, eliminating the need for manual operations each time. For long-term but uncertain storage needs, this mechanism helps better control costs — avoiding waste from setting excessively long periods and reducing the need for frequent manual management.

This approach finds a balance between the economics and practicality of on-chain storage.