“At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly.”
This is one of the principles behind the Agile Manifesto. While following all the principles is essential to being agile, one might argue that without tuning and adjusting team behavior on a regular basis, productivity gains will be hard to achieve.
Unfortunately, many read the above principle and only associate it with performing team retrospectives at the end of a sprint, or periodically in kanban. But if you seek to build a high-performing team, there are many more improvement activities you should consider adopting.