Question: I just noticed that we have both an [nsdocumentdirectory](https://stackoverflow.com/questions/tagged/nsdocumentdirectory "show questions tagged 'nsdocumentdirectory'") (52 questions) and a [nsdocumentsdirectory](https://stackoverflow.com/questions/tagged/nsdocumentsdirectory "show questions tagged 'nsdocumentsdirectory'") (136 questions) tag - the only difference being the pluralization of `document(s)`. Which one should we keep?

Answer: 
Merged and synonymized.

Also, knock off the "how can there be an expert in..." crap - you don't need to *dedicate your life* to an API to garner some knowledge that can be useful to others. I've certainly spent some time monitoring fairly obscure tags after wasting an afternoon on worthless documentation, and I'm sure others have as well.
The actual API is [NSDocumentDirectory](https://developer.apple.com/library/ios/documentation/Cocoa/Reference/Foundation/Miscellaneous/Foundation_Constants/Reference/reference.html) (no "s"), so if we keep one it should be that. That said, I agree with Richard's comment, the tag seems entirely unnecessary.