Tsh - there are simply more townhomes than single family homes... and people who buy townhomes are, like yourself, planning to be there for only a few years, so we see more turnover. The people who live in a home forever very often are focused on single family homes, if their budget allows. In general, because townhomes are more affordable than most SF homes, I personally think they sell faster... but that is a very general answer and not fully reflective of all situations.
I work in Fairfax and Loudoun Counties in Northern Virginia, and would love to assist you.
Feel free to use the Home Search option from my web page http://(www.VickyChrisner.com
) , it links directly to our local MLS and is updated in real time. I also have many resources for preferred lenders (Service Providers page) in our area and just general area info (schools, transportation, etc.) under ABOUT THE AREA.
If you're looking in Arlington, Prince William or some other part of No Va, I'd be happy to refer you to a colleague.
Best of luck,