I hear many native speakers dropping auxiliary verbs when asking questions. For instance, I hear them saying "How you doing?". Another example that came up to my ear recently: in the gym, I hear many native speakers say: "How many sets you got?" To ask about how many more sets you need a machine. This question doesn't sound well-structured. I think native speakers drop the "have", so the question was "How many sets have you got?" don't they?
How and when native speakers drop/not drop these auxiliary verbs when asking questions? Do "educated" native speakers speak like that also? Because someone told me that this language is used by noneducated people, but I'm not sure if this is true.