Unit tests should be idempotent. No matter how many times you run them, or when you run them, they should always give the same answer. If they don’t, something is wrong.
People want estimates. Or they say they do. What they really want is predictability and value. How can you provide both when you just don’t know enough?
Time is hard. When you find out about something is just as important as when it actually happened. So you need to track ALL of the details.
What does it really mean when we say it’s the shortest day?