"Vacation" comes from the Latin vacare, meaning "unoccupied." Seeing as we don't speak Latin anymore, you have no reason to know that. In fact, this knowledge may be displacing important information in your brain, such as what to do in the event of a mountain lion attack or how to prevent forest fires. Please take this time to forget everything you know about the Latin origins of "vacation."
Good—on to more pressing, 21st century matters. Email used to be like having an secretary whose desk you could swing by and ask, "Any messages?" Nowadays, email is more like an atmospheric gas that enters your smartphone through desublimation and buzzes your thigh to tell you, "Use this code to get 15% off your next purchase at Bed Bath & Beyond." It's always with you.
Humans aren't designed to be constantly reachable. We need alone time, which is why we have eyelids. We also invented vacation, which was intended to be a protracted absence from whatever it is we are always doing. Nowadays, that includes email. Here is an important guide to getting away from the persistent hauntings of electronic mail.
Tell People Who Depend On You That You Are Going Away For A Bit: People who fall into this category include, but are not limited to: bosses; coworkers; immediate family members; roommates; dog sitters; cat sitters; constituents; teammates.
People who do not fall into this category: Facebook friends; Twitter followers.
I am on vacation. I will be able to respond to your email when I am not on vacation.
Setting up one of these responses is one of the most socially acceptable forms of boasting, so please relish this step.
Don't Look At Your Phone: If your phone doubles as a watch, either A) buy a cheap watch (you can find one at a local drug store for under $10) or B) don't worry about the time.*
*B is not applicable if you made dinner or Jet Ski reservations. In that case, care about the time somewhat.
Don't Worry: If you left the oven on and your house burns down, the fire department will not inform you via email.
Don't Use The Hotel's Business Center: This is a glassed-in chamber of temptation. Every time you feel like going in there to check your email, go on a fanboat tour or parasail instead.
Talk To People: This is a good, non-email way to communicate that was made popular sometime before 1995.
Don't Check Your Email: This is the most important step. Use this mnemonic device to help remember: "Dean Cain Yells Excitedly Because You Are Overtly Vicious, Jeeze Don't Cry Immediately" --> Don't Check Your Email Because You Are On Vacation, Just Don't Check It.
Check Your Email: Or don't, actually. This one is up to you.