Hourly planning is at the heart of every project management system. Planned Hours and Remaining Hours will help you stay on track in the future and can give you an indication of how well you are planning your tasks.
You should define planned hours at the start of every To-Do. How many hours do you think you will be spending on this To-Do. This should only include dedicated work towards this To-Do. You do not want to change this number once you started working on your To-Do. Leantime uses the planned hours to determine the hourly sprint burndown. Changing it later on will skew the results.
Remaining Hours are the hours you believe are still left on the To-Do. Ideally you will update this number every day (or every other day). Remaining Hours is a forward looking assessment and does not include worked hours. This means that your hours could remain the same even though your worked on a To-Do.
Kate planned to work 5h on Task A. She finished the task the same day and updated the remaining hours to be 0h.
John planned to work 6h on Task B. He worked two days on this task and found a lot of dependencies that were not clear before. He believes it will still take him 6h to complete the task. He leaves planned hours and remaining hours to be 6h.
Jane planned to work 2h on Task C. After some additional research she found out that this task will take here at least 8h to complete. She leaves planned hours to be 2h and updates remaining hours to be 8h.