Let's say you're working by yourself on your pet project. It's entirely for your personal benefit, and no one else matters. Why would you want version control?

* when you make a change that introduced some bug, you can see exactly what was changed, and roll it back

* when you delete a feature because it's no longer useful, then some time passes, and you realize that feature is useful (or you can use that code for something else), you can just pull up your old code and re-add it.

* you can delete old stuff, knowing that it's not in fact gone.

* you can do more radical experiments by branching your code. While you could do this without version control by just copying your code to a new location.. with VC you could keep all of the file/code history.

I work alone writing software projects. No one has seen my code in 10 years (since I started). I use SVN. Every bit of code gets put in SVN.

If you aren't sure about version control, take my word for it: you want to use version control. It will make your life easier. Just do it, and in a short time, you'll see exactly what I mean.