The reason why you don't hold a unit for someone.

[Ryan Dossey]

There is a reason why most experienced landlords say that you have to be strong and tough. If you give an inch people take a mile. We had a home that we were trying to rent around New Years/Christmas. A tenant applied using smart move and everything looked good. She had good credit, work history, and no evictions. She asked if we could hold the home till she got paid next. 2 weeks? Sure no problem. She was supposed to move in tonight. I called her and she told me that she had a car problem and couldn't afford deposit or first months and was sorry for wasting my time. I literally turned down 10-15 interested parties because it was "already rented". Learn from my mistake!! I know I sure did. 

[James Wise]

You have to collect a deposit to hold a house.

Do the daily rate. Rent / 30 = daily Rate.

In this case if rent was $800 collect a $400 non refundable deposit to hold for 15 days.

Tenants who pay this deposit still back out believe it or not. But at least you were able to get paid for the days it was off the market.