It varies. Sometimes it's 6pm, sometimes 24, 48, 72, sometimes 2 weeks, sometimes 30 days. Depends on the property & the situation. And there have been some properties that unless you cancel w/in 24hours of MAKING the reservation you get hit w/ full fare (encountered that in a sold-out city-wide event one time, but luckily caught it before pushing the reserve button).

BTW aaupgrade, several years ago Vail Marriott had a once you hit the reserve button you were charged upfront & it was non-refundable. I got stung w/ that one once, and had to jump through hoops to get it reversed.

Cheers.