I've never done automated testing, but as I've grown as a developer and started dealing with more complicated codebases, I have come to see the importance of testing in a huge way.
With a small codebase that you know every inch of, its easy to test most of your interactions before you push something live, but when you get just one order of magnitude higher you start seeing how easy it is to write code in one section of your app, test it rigorously, but not catch some subtle breakage in another (seemingly unrelated) section of your app.
In production software, especially if you have paying clients, this is simply unacceptable; which is why I've recently been boning up on BDD, TDD, and continuous integration and am trying very hard to slowly integrate them into my development process.
To one of the comments before, in my experience, automated testing should actually makes you bolder with code not more fearful. We have this codebase where I work that is a frickin mammoth of interrelated modules and its so scary to go in there and add or change something, because I just know something else is going to break and I'm going to be stuck fixing it for days after I made the first edit.
This is the other reason I started exploring automated tests ... because I realized that if I had a test suite that could catch regressions when I refactor code, then I could actually spend more time whipping old code into shape instead of patching it up until such a time when I'd be able to just rewrite the whole thing.
With a small codebase that you know every inch of, its easy to test most of your interactions before you push something live, but when you get just one order of magnitude higher you start seeing how easy it is to write code in one section of your app, test it rigorously, but not catch some subtle breakage in another (seemingly unrelated) section of your app.
In production software, especially if you have paying clients, this is simply unacceptable; which is why I've recently been boning up on BDD, TDD, and continuous integration and am trying very hard to slowly integrate them into my development process.
To one of the comments before, in my experience, automated testing should actually makes you bolder with code not more fearful. We have this codebase where I work that is a frickin mammoth of interrelated modules and its so scary to go in there and add or change something, because I just know something else is going to break and I'm going to be stuck fixing it for days after I made the first edit.
This is the other reason I started exploring automated tests ... because I realized that if I had a test suite that could catch regressions when I refactor code, then I could actually spend more time whipping old code into shape instead of patching it up until such a time when I'd be able to just rewrite the whole thing.