If you feel like your inbox has a habit of growing from a small hill into an unassailable mountain, then this may be the trick you need.
Three sentences is permission to treat your email like you would an SMS. Simply limit your reply to three sentences or less.
Focus on only communicating the most important information. Do away with the formalities. Don’t fear coming across as brusque; people will come to respect it.
This is just another opportunity and example of letting self-improved constraints work their magic.