As a professional developer I test my code. Every check-in I do is tested either on Kabisa’s Jenkins server or on Travis CI Pro.
For open source projects there’s Travis CI. It’s free and a great way to get to know Travis.
Now, as an individual I have some side projects, most notably my own site, Ariejan.net. I value well written and well tested code as much for my own stuff as for my professional work.