In my personal experience, most bugs come from changing a working code, especially at a refactoring. It mixes assumptions in an unpredictable way, because of ch

In my personal experience, most bugs come from changing a working code, especially at a refactoring. It mixes assumptions in an unpredictable way, because of chaotic code rearrangements and lots attention required to do that correctly. First-time code is much easier to challenge (if you ignore repl development phase which is not “code” yet).