Hi alexbcf,
There is no out of the box functionality which you can use.
The workaround that I can suggest is, give the power to purge a list to the same workflow that creates the list.
Once a day on that workflow, before starting the transition that go ahead with purging 30 days older data and once it has done by reading list, identifying data which is within the last month, scope, merge it with the new data that should be part of this list using Union activity, update the list using the condition delete and recreate the list.
Regards,
Vipul