When switching between different source code management systems for doing version control at clients, it is always a bit of “getting used” to the mantra of both their system, and how it has been implemented.
Few people can really explain this well.
I still see truckloads of people, and even teams try to do without version control. Please do use source control. If you don’t know where to get started, read some text on Source Control for beginners, or for instance the free on-line Red Bean books on SVN, Mercurial or CVS.
Also read some other great answers by Richard Berg (many on TFS, but also this very balanced view on usage of nullable in languages and proper use of Invoke-Expression in PowerShell: recommended reading).