You don't need to work in an extremely repeatable domain to get good at estimation. There is very little in my day to day job that is repeatable, but I can roug

You don't need to work in an extremely repeatable domain to get good at estimation. There is very little in my day to day job that is repeatable, but I can roughly look at the project I'm on and compare the scope of it to the projects I've done before. If you really do think that every project you're working on is completely incomparable to anything you've worked on before you're probably concentrating on too low level details.