It does not matter that you can estimate 99% of [simple] tasks. The total time is dominated by complex (big uncertainty) tasks that you can't predict/estimate r

It does not matter that you can estimate 99% of [simple] tasks. The total time is dominated by complex (big uncertainty) tasks that you can't predict/estimate reliably (e.g., think lognormal random distribution). Programmers are good at automating predictable boring tasks. If you are competent, there always be unpredictable elements in your work. Software estimation is similar to the coastline paradox if you don't know how small your measuring stick should be in advance. The smaller the stick the longer the coastline might be (fractal nature). An analog of taking a big software task, splitting into several smaller tasks and using it as an estimate would be like drawing a square on a map and rely on it as a good estimation for the coastline length that you can use for any scale (it is wrong if the coastline is a fractal (if the software task is complex)) https://youtube.com/watch?v=I_rw-AJqpCM https://youtube.com/watch?v=I_rw-AJqpCM