Leaving for the holidays...
Manage peoples' expectations ... and your own.
First and foremost, decide how available you are going to be during the holidays and from there you can set expectations for the people trying to reach you and for yourself. The easiest way to to do this is with an Out of Office message for each email account you have and for your phone(s).
No matter what your holiday plans are I think a great idea is to let people know what your company's holiday policy is, regardless of whether you are taking vacation time or not. It takes 1 minute to record a personal message letting clients and suppliers know when the office is open during the holidays. Then I suggest more details, such as:
Whether you are working through the holidays and will be available as usual.
Are you taking vacation time but accessing your emails sporadically. If so, give them an idea of how often and if you are planning on answering emails at all.
If you are not working at all and will get back to them when you return to the office, let them know what date that is.
Is there someone they can connect with if there is an emergency? If so, give the name and coordinates of this person and invite them to reach out to them in the interim.
Set yourself a calendar reminder to do a quick Weekly Review before you leave the office for the holidays. Quickly look forward in your calendar to the day/week you will be coming back, take note of the first meetings you'll be attending, is there some preparation expected from you, start a next-action/to-do list, jot down a few ideas or thoughts that will need your attention when you get back. Remember, as David Allen says 'Your mind is for having ideas not holding them'.
Don't spend your holidays worrying about work and whether people will be expecting to hear from you or not ... let them know what they can expect from you.