Most open houses take place over the weekend when the general public is more able to preview homes. I have learned that about 95% of the people that come an open house either know a realtor or have one within their family they will use. That leaves 5% that are not working with a realtor. Of that 5%, out of curiosity, some are neighbors interested in the asking price so they can use it and other information for a comparison to their own home. The remaining small percentage end up driving by the area, notice the open house signs your agent strategically placed at each corner and walk into your house. These are strangers, possibly unqualified to purchase your house, and not only that, but your house may n ot be the right fit or style they are looking for anyway. Then there are those people just passing the time of day.
That being said, those that become disinterested in your house now become a prospective buyer of another house that your realtor would be happy to show them. So, now are you surprised that an open house usually benefits the realtor more than the home seller? I'm not saying an open house is necessarily useless. There have been lots of cases a home sells as a direct result of an open house. The percentage of homes sold as a direct result of open houses is minimal to say the least.
Your realtor's time is very expensive. You are paying your realtor a nice hourly wage via a commission to market and sell your home. Do you feel that nice hourly wage should be spent baking cookies and permeating the house for a possible buyer or spent wisely on mass marketing media, networking and other more effective marketing strategies? I'm sure you can answer that one.
I have to admit I would be very upset if there was an open house at my house and my realtor was discussing other houses for sale with other potential clients. After all, I pay that realtor a good commission to sell my house in a timely manner.
The thing to remember is to stay focused on the priorities of selling your home. What is required to sell your house? That's the real question because you must remember this is now no longer your "home." It is a house to be marketed, so put away all your family pictures and too personal things that will cloud the potential buyers eye to see their possessions in the house. Ask your realtor and then do it. If it means cleaning out the house or painting, do it. Do whatever it takes and your house will sell in a timely manner.