You can set the expiry time for your escrows to be anywhere from 12 hours to 1 week after the time they are opened.
As long as the exchange has not become unresponsive, you will be able to close your user escrows at any time before they expire. If the exchange becomes unresponsive or behaves improperly, you will be able to close your user escrows after they expire.
You can close an exchange escrow early, any time before it expires. Closing an exchange escrow early will earn you a rebate on its escrow fee.
To keep you coins safe, even if the exchange is hacked, unresponsive, or loses access to its wallet, you must remember to close your escrows before they expire.