15 minutes

15 minutes is a magic duration.

Everyone has 15 minutes. For example, if a team of some dozen people decides to go to lunch together, 15 minutes is about the time spanning between the moment the first team member says "lunch?" and the moment in which the group actually goes to lunch. This 15 minutes is a dead time anyway, so if you want to utilize it for something productive there is no need to ask for permission. The budget is already allocated.

Everyone has 15 minutes. But, 15 minutes is also long enough to actually do something with it. 15 minutes is about the time it takes for a good stand-up meeting. 15 minutes is about the time it takes to have a good brainstorming session. 15 minutes is also about the amount of time it takes to perform, test and commit a simple refactoring.

15 minutes is truly magical. That is why daily assessment relies on it.