Checkpoints are a simple but effective productivity tool.
They are a way to:
review your progress towards goals;
ensure that you have not become sidetracked by non-critical activities; and
allow you to course correct before you go too far off-course.
They can be built into your calendar as a regular activity.
They can be completed alone or with team members, which takes the guesswork out of whether everyone is on the same page.
For example a salesperson might checkpoint their progress against targets twice a week … perhaps Friday evening or Monday morning, and again on Wednesday. This way the rep might find they are falling behind in some important metrics, or that upon a sober second look, they might get better results by focusing elsewhere. They can course correct at any time rather than getting to the end of the month and realizing they are too late to make a difference.
If you have multiple projects or responsibilities checkpoints are particularly useful because without them it would be the “squeaky wheel” projects that would get attention .. and that is not usually the best answer!