Everyone's different. I think there are people who can't enjoy their vacation if they know that something ominous could be out there waiting for them when they return. These folks should probably set a time every morning (or evening) where they check email and voice mail once a day. I would let people know in advance that you're not going to be as reachable, but everyone will get an answer.

For me, I need to completely unplug on vacation. I even vacation specifically in a place where I have to drive several miles just to get a cell signal. When they improve reception down there, I'll simply turn off my cell phone and lock it in a drawer or something. I still feel the pull of being needed and wanting to respond, but I fight that impulse.

To get ready for vacation, I make sure there is a contact person for each of my major initiatives, and that everyone who might need it has their contact information. Here's how I schedule vacations:

- 1 week before, setup go to people to take the traffic
- 2 days before,
-- quick note to my important clients and stakeholders about what to do while I'm away
-- email to get my go to people up to speed
- 1 day before, meet with contact people if necessary to get them completely up to speed
*** VACATION *** - no contact
- 1st day back,
-- I usually "cheat" and tell external folks (not my go to people) that my vacation is still going on.
-- Use the time to catch up on email and voice mail
- 2nd day back,
-- Meet with go to people to debrief anything I wasn't CC'ed on

I know not everyone has the ability to unplug like I do, but if you can at all, I highly recommend it. Sometimes we think that we're vital to everyone else, but they can usually find a way to get along without us. :)