The only point of listing with an agent is to get access to the MLS. After that it's only business. You are trying to maximize your sale and all the agents are trying to close a commission. I don't begrudge them that because I accept the costs of the service prior to listing.
Now if agents were responsible for actually cleaning your property before each showing then I would retract my previous statement.
That's not true. Real Estate agents do a lot more for clients.
1. They help set the price for you. Look what happens when people are left to set their own prices in vehicles? I saw an $8000 1996 Toyota Corolla last year in the Autotrader (private listing). How quickly do you that sold at that price?
They can give you a realistic market value.
2. They should be giving advice on how to make your home more appealing. You may love your burgundy floral wallpaper, but others may not.
3. They do the negotiating, they talk to the other agents, they field all the calls. They deal with people during a highly highly stressful period in their lives. Often for long periods of time.
Now, a good professional agent does all that. However, any seller should so their due-diligence and interview prospective agents before you decide on one.
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If you're prepared to accept all responsibility then listing your house privately is also a viable option. Some do well, some sit on the market for months and eventually get listed by an agent. I think it depends on the market.