I received this letter today. My husband says I work for thank you notes and I have to agree. 
"Dear Margaret:
We find it amazing that we never got around to thanking you for all of your effort in selling our home of over 41 years.
Phyllis and I were talking about a range of things last night, and the conversation came up about some friends who could not understand why we did not try to sell the house ourselves in such an active market, or use one of the discount realtor services. Everyone seems to have stories of houses sold to the first prospect, even before the "For Sale" sign went into the ground.
I guess some people feel that they must squeeze every last dollar that they can get, but perhaps they fail to recognize that there is not only the price, there is a cost. I question whether or not the costs of doing it yourself worth it?
In looking back we had no idea what a realistic asking price should be, how long our house might be on the market, and what improvements, beyond a new roof, we might have needed as a result of inspections. Unknowns for us, but not for you.
We would have been more than a bit overwhelmed and crazy with the appointment process, the last-minute cancellations, the no-shows, etc. Not to mention answering the prospective buyers questions about every appliance, the heating system, the windows, the plumbing, the electrical system, the ceiling, the fireplace, the "chimley," and of course, what kind of floors are under the carpeting. We had confidence in you, so we just let
you do the work, and thank you for doing so.
You gave us an appropriate level of guidance, you emphasized "curb appeal," and you reminded us that we still had to live in the house while it was for sale. I think you implied that a perspective buyer and/or their realtor would recognize this fact. Our not being present allowed the prospects to look where they wanted to look, ask the questions that they wanted to ask, and to voice their opinions, concerns and objections to you freely.
Hindsight is often be "20-20." But as we look back we truly had no idea about how to sell our "home."
Our experience convinced us, that sellers should always use a knowledgeable realtor when selling their property. The right realtor will do their best to make the process as trouble free as possible, save you loads of time, and get you the best price that they can.
That, Margaret, is precisely what you did, and we sincerely thank you."
Phyllis and Mort
July 20, 2006