From agreeing to the sale of my house how long or at what point do I have to back out of the agreement

From agreeing to the sale of my house how long or at what point do I have to back out of the agreement

Normally this would be right up until you sign the contracts, but it depends on your location.

Read the terms of the agreement. If nothing is in writing and no money has changed hands you can back up at any time. If there is a written agreement, especially if money has been paid, this should be spelled out in the contract or agreement.