I did hear of this company which is not using version controling, we all did hear of this one company. But did you ever hear the name of the company? I didn't! There must be a company, not using version control to develop their software, but nobody tells you the name of the company. I even heard stories of companies that develop software for libraries for which they did lost the source code.
After quite some time hearing these stories and never hear a name, I thought these are just fairy tales. Fairy tales! Like the ones parents tell their kids to scare them. Well nobody can be that stupid! Nobody is developing software without version controlling (at least not for projects in teams and not for projects that run longer than a week, but even then it would be a good idea). No, that would just be stupid! Software development without version controlling is like bungee jumping without ropes.
But last week, not thinking about these stories anymore - I found it! I found the company not using a version controlling system, this company does really exist. And off course I'm not gone tell you the name of the company. I don't want to blame them (in public). But trust me this company does exist! They save their files on the disk and try to not work on the same files as there coworkers do.
But too scare you not too much: They will switch to a version control system soon. So the company using no version controlling is soon history. If you really should find a other one (or, behave, work for one) tell them to install a revision control software. Install one as soon as possible not matter which one (as long as it is not source shredder, ähmm safe). Git, SVN, CVS - they are all fine! As long as you use one.
You might probably not believe what I say. But please believe Bertrand Delacretaz, he's a director of the Apache Software Foundation (this guys manufacture the internet), and in his talk he does also tell you the next three step after having a version control system. You find the slides and the video recording here.