Question

I need to collect statistics on the lead time for each task.

For example I have 4 statuses
Plan
In Progress
At checkout
Done

And I want to know the dates of transition from one status to another, as well as how many days the task spent in a particular status

Answer 1

The easiest way to do something like this in Notion is to use Sub-Tasks.

Main Task
-- Plan
-- In Progress
-- At checkout
-- Done

That way you can track each one independently as you need, have start and end dates for each one of them and mark the Main Task as done when all the Sub-Tasks are completed.