Is there a particular property you are talking about? Are you renting as a weekly or short term rental property or are you just asking a question? Are you renting from an individual, a landlord, a rental management company?
I am not sure what you mean, but if it is a rent back after a sale this is how I do it. Figure the new owners monthly PITI and divide by 30 days. Then multiply that daily amount by the number of days you will stay there - 9 in this case.