It's the same best practice you would follow in developing an actual application. As far as I know, in an environment where there are multiple developers working on an application, they each have their own copy of the source they develop against. They then use a source control application to control who has access to integrate a change into the main body of the source, allowing comparison between versions, etc.
The same holds true with TC, as far as I know. If you have multiple people working on a scripting project, it would probably be best to incorporate some sort of source control solution if you haven't already.
Automated Testing Evangelists
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