If you are considering Kimai for personal or team productivity, start with a week of real work. Define a small set of projects and activities, record time as it happens, and review whether the reports answer a question you actually have. Do not create dozens of categories before seeing what people can maintain accurately.
Check corrections, permissions, and exports, especially if entries may support invoicing. A useful tracker gives a trustworthy picture of effort without making every short task an administrative chore.