[sdegutis]

Experience alone doesn't help you get better at estimating. You also need to have reasonable stopping points. That's why I try to aim for rigid 8 hour days, rather than being flexible. It allows me to see how much work I accomplished in a given day, and what kinds of tasks generally take less time or more time. Days are very intuitive chunks of time to reason about, and I find this helps my estimations be a lot more accurate.