I worked at a company that didn't employ any unit testing and they were terrified of updating their aging software stack because it was constantly breaking as i

I worked at a company that didn't employ any unit testing and they were terrified of updating their aging software stack because it was constantly breaking as is. I was doing greenfield work and was paranoid about losing data, so I had extensive test-coverage. I undertook multiple complex refactors of the codebase and never had a problem thanks to my unit test coverage. My code was never the cause of any major data loss and I found plenty of very serious bugs in the legacy codebase.