Impromptus

What about “commenting out” parts of the code you don't necessarily want but don't want to outright delete? I know this isn't a good practice, but is it still common, or has version control made people less likely to do this?

One amusing thing: if you upload article to the arXiv written in LaTeX, the arXiv makes the original source available. Hence, if someone has “commented out” parts of an article, and forgot to strip the comments before submitting, it's actually possible for everyone in the world to read the comments. The arXiv online help even has a Perl script you can use to get rid of “potentially embarrassing self-comments”.

The ability to not have to do that is the whole reason to use version control. Version control is there so that you can throw out old code and still be confident in your ability to retrieve it. People who use VC generally avoid the “comment out old versions to save for later” practice, and people who don't, don't.

This is actually why you should use it! Do you? I recommend http://github.com for free VC hosting, but you have to use git (as opposed to Subversion or CVS), which may be difficult and annoying to set up on Windows.

Why version control?

I have a private repository on Assembla, which costs a trivial $2.30/month. (Like github, they charge you money if you don't want your repository to be publicly visible.) I started using version control after collaborating with a group of mathematicians who used it to coordinate their collaboration. I loved having version control when I wrote my dissertation. As you stated in your “Why version control?” post, it made me unafraid to delete or radically reword passages.