We just finished our 3 day garage sale, we joined in our neighborhood association second annual sale. Let's just say I am glad it is DONE.
The weather was less then perfect, it rained on and off the first two days and was chilly (for summer) and windy. In the end we did sell about 200.00 worth of stuff and did some decision making to donate a bunch of stuff including several boxes to go to the library book sale.
I would do one again but not for 3 days, and would try to cut back on the amount of stuff so it is less to manage, we also have it in our yard so we had to do a lot of moving back and forth.
On a plus side we hired "College Hunks Hauling Junk" to come in advance of the sale to haul away about 4 pieces of heavy furniture that we could not do ourselves. They kindly posed for a pic.