When you sell, I assume you want the best price for your home.
Homes that sell within the first 30 days sell at closest to asking price most of the time. In my market homes that are on the market sell for 93.6% of asking at 120 days. Within 30 days it's 98.6%
For single family homes, it's currently 87 days versus 66 a year ago. To be honest, I'm not sure if they still use average or if they've converted to median, but should be resosnably close for large amounts of data.
As stated by the previous posts, individual homes within the same subdivision can vary significantly, so the average for the whole market is pretty much just an interesting number when considering a specific situation.
Give me a specific location and I will give you a more specific answer. You may reach me at (210) 273-9082.