Rule #2
Estimating - Do you know what tasks are involved in addition to just Development Work Items?
  v8.0 Posted at 7/08/2012 5:30 PM by ulyssesmaclaren
Just like how a beautiful house is more than the bricks, a software project is more than the sum of the coding tasks.

Let's see what should be included :

In fact, for every 1 hour of 'application building' coding tasks there is between 1 and 4 hours of other work which SSW will charge for. This other work includes administration, testing and bug fixing.

Here is a list of the items which SSW considers when estimating a release.