Do you refund if the tenant stays less than 30 days on the lease

Hi,

In our lease we ask our tenants to provide a 30 day notice if they do plan to leave. If the tenant decides to leave lets say on the 20th day, are we supposed to credit them back the 10 days that they have not occupied the lot? The mobile home belongs to them.

No credit due. Notice is actually the length of a full rent payment (month) not actually 30 days. The 30 day notice should be provided before the end of the previous month.
If a tenant gave 30 days notice on the 1st of June the thirty days (month) notice would then be to the end of July not the end of June.

What does your state Landlord Tenant Act say about length of notice required. 2 months notice would be more likely the requirement.