I also write a lot of tests. Sometimes before a new feature. It does take quite a bit of time; more time than the actual code in most cases. It also protects against shipping bugs, losing customers, late night emergency patches, the next dev’s insanity, regressions, bad upgrades, doc errors, impossible refactoring time…; and in my current $work industry in particular, it prevents lawsuits. After a year or so, it has amply repaid the initial time sink.