The general rule of thumb is that garage sales open between 8:00am and 9:00am. This rule normally applies to Friday, Saturday and Sunday sales. One of the strongest tips that anyone can give for a successful garage sale trip is simply to beat the competition. You must get to the good stuff before the next guy. If that means losing an hours worth of sleep on the weekend, so be it. To be a garage sale professional, you must sometimes sacrifice some things. Never in my past experiences have I ever been told to leave a garage sale when the people were still setting up the displays. "The early bird catches the worm" has never been so dead on when it comes to garage sale hunting.