The length of the courtesy hold will depend on when you want to arrive. If you're within 14 days of arrival, Disney will not allow a courtesy hold. If you're within 15 to 45 days of your requested arrival date, Disney will hold your request for 24 hours. If you're 46 or more days outside of requested arrival, you'll be able to hold the reservation for 7 days.
As the PP stated, 2016 brought changes to deposit and final balance due dates. Deposit is due 3 days after booking and balance is now due 30 days before arrival.