Originally I wanted to title this "Last night Eclipse saved my life" but decided that didn't really explain this mini guide all to well.
First off, if you are not on Eclipse than you probably don't know about two great features, "Compare with local history", and "Replace with local history". In brief, Eclipse saves all previous version of your file(s) you are working on. So with a simple click you can "Compare"/"Replace" your current version of a document to the original one you started working on 2 days ago! Think of it as a mini source control without the checking in.out. If you want to know more about these features go to Robert Blackburn write up in Fusion Authority.
What does "Going beyond Eclipse's local file compare/replace" mean then?