This really depends on the size of the project and how many developers are involved for me. If it's just me and there are no external users then I almost never

This really depends on the size of the project and how many developers are involved for me. If it's just me and there are no external users then I almost never write them due to priority. If there are external users and/or at least two developers, then absolutely. It's a great sign people are writing automated tests for their side projects because based on my experience there are still many teams that aren't bothering to do so for bigger production projects adequately. It's one of those things everyone knows they should do and talk about it but the resources and priorities are almost never in place. The test results need to be visible by more than just the testers too. I have a particular interest in test automation due to my involvement at Tesults (https://www.tesults.com https://www.tesults.com). This is a test results dashboard for teams of about 10-20 or more - it's not designed for tiny teams or side projects but if you're interested in trying it out for a small team send an email using the address on the site with the link to this page on HN and we can sort you out - only really worth it if you are doing continuous build/integration too, overkill for one or two person teams.