Our sprints follow the pattern of a planning game based on a prototype, followed by actual application development with unit test, followed again by integration test and more complete unit tests to try and achieve code coverage goals.
In planning two/three week sprints we often find that after allowing for tasks such as developing prototypes, retrospectives, planning games, and deployment and test support tasks we are only left with less than 50% of the days developing the actual user story functionality - this is in planning, before we even get to the unexpected distractions that can occur in reality. Is this typical, or is there a good benchmark for number of ideal days to aim for? Would we be better to focus on optimizing time spent coding, or simply allow for this velocity in planning.