A recommendation in this day and age, when using TFS for team collaboration, is to use the help from Mercurial or other modern code versioning tools for local changes and offline usage. There is no need to list all the benefits of Mercurial right now. Suffice to say that it provides painless safety net with branching and merging support that allows easier work.
An article at Los Techies describes the scenario how this can be accomplished. Basically, after checking-out the TFS project, create a Mercurial repository there. Get a MakeWritable extension. Clone the Hg repository into a working copy where you will be making changes and that's it. Use the scripts below to check-in/out from TFS.
PowerShell scripts are located in an online repository.