If you rent out one of your rooms or a cabin on your property, what is the minimum number of days you can rent it out before you are required to pay sales tax, lodging tax, etc... it would normally be 3-5 days a month.

You become liable for taxes once the number of days exceed 14 days per year. However, you can also begin to deduct the expenses associated with the property as well.

Because you make personal use of the property, the expense costs CANNOT exceed the income, but everything must be reported on Schedule E.

This varies from state to state, where are you located. Are there city or county requirements to qualifiy to become a rental?

The advice noted earlier is for the FEDERAL tax return and thus it is irrelevant as to which state is involved.

The state tax on the rental income will depend on the tax laws of the individual state.