Using version control is vital to a development shop. Even though I am one developer, I have a subversion code server in my basement that I constantly use. If I write a bad piece of code, it feels so good to rollback to a previous version of code instead of trying to wrack my brain figuring out what code to back out.

In a team or corporate environment, though, you may have some developers who are new to the team and are unfamiliar with version control software likeI know those coming from Microsoft SourceSafe to CVS had some troubles adjusting.

CVS or Subversion. These commandments are definitely required for any new or seasoned developer.