What happens to completed tasks?

[mgkimaero]

Hi I have a few questions about tasks

1. What is an "active task"? Is a task that is marked "completed" still regarded as an active task? 
2. What happens to a task after it is marked completed? Is it saved or archived? For how long? 
3. I saw in the "Limits" documentation that individual planners are limited to 2400 active tasks. What happens when this limit is reached?

I am using planner to manage my personal work load and would like to have access to all the tasks I completed in a Fiscal Year so that I may export them and use them for my end of year review. 

Any information or suggestions would be welcome. Thank you.

[#2]

Hi,
My 2 cents here:
1. The concept of Active Task in my opinion means a Task not completed
2. Is stored forever unless it is deleted
3. You will not be able to add more Tasks to the Planner Plan