So is "Just use a hash." overworked? As long as it is seen as a common idiom to employ when the situation fits, no. Once it becomes a thoughtless mantra, perhaps.

That's unnecessarily overqualified. Any time anything becomes a thoughtless mantra, it's a given that it's over- (and improperly-)worked.

As I often say, the best thing about {rules, best practices, coding standards, etc} is that they let you do things without having to think about them. The worst thing about them is that they let you do things without having to think about them. (Shoot, there's a whole Meditation in ringing on the corollaries to that ;)