I have seen many people staying motivated and organized with help of plans.
I also have seen negative shade of planning. People with one type of OCD tend to make plans and overthink about them.
I see a clear demarcation. Healthy plans that reduce stress are the plans made by considering measurable and certain factors. For eg: If I plan to do mphil from year 2023 to 2025, that is a healthy plan.
Unhealthy plans are obsessive thoughts abouts things that are irrational, uncertain and beyond human control. Eg: if I plan to save money that is enough to undergo cancer treatment, by assuming that I might get cancer in the future (if someone genetically related to me has cancer and there are actual chances of me getting cancer, that is a different case). Someone’s death, diseases, breakup, fears fall into either category of things that cant be controlled or in the category of irrational thoughts.