When you move in, we require you to pay one month rent in advance. If you do not move in on the 1st of the month your second month's rent will be pro-rated to 30 days after the move in date (regardless of the number of days in the month). We use 30 days to make this calculation  as this is standard procedure in the rental industry. 

Eg, If you moved in on Dec 20th your second month's rent, will be due on Jan 19th because your first month's rent paid for the period Dec 20th - Jan 18th (30 days) and will be due for the period Jan 19th to Jan 31st.

The same method will be used to calculate pro-rated rent when you move out