I don’t respond to any e-mails from classroom students of any kind. Period. I make this policy known at the beginning of every semester, and let students know that if they would like to make an appointment to talk to me, they can call me on the phone.
When I was a student, there was a serious activation energy required to disturb a professor. The idea that students should be able to just text message professors from the basement of the motherfucking fraternity and the professor is supposed to respond is ludicrous. Fuck these little overentitled pissants.
UPDATE: Just to clarify: I used to accept e-mails for the purpose of making an appointment to see me, but half the time the students didn’t even show up. That is why I recently modified my rule to require a phone call to make an appointment to see me.