We want to automate the build so that it is easy to use. We wanted it to be so brain-dead simple to use that we use it all the time and we invoke the build whenever we make even a minor change to the system. This is how we get the most value from our build — when we use it all the time.
To facilitate this we have the idea of the one-click build, which means that you can invoke the entire process with a single click. We can set this up so that when we save a change it re-compiles all of its dependencies on the local machine and then runs tests on the local machine. If these tests pass the changes are pushed up into the build server and a more complete set of tests are run against it. All of this should happen automatically. Ideally, we want the build to run fast and that means anywhere from a few seconds to a few minutes.