But I also believe there’s meaningful power in the mundane cultural norms we set and practice. Email, for better or worse, makes up a large chunk of how knowledge workers communicate. So much of this communication is muddled by broken email habits and larger anxieties around performing productivity. We’re constantly nervous about asking too much of others or doing too little on behalf of our coworkers. But we’re also stuck in work patterns that force us to communicate constantly and normalize working and demanding things from colleagues at all hours.
Out of the Office but Reachable Message. Not every vacation you take is going to leave you completely unreachable. For those days when you’re out of the office but are still checking and responding to email or phone calls, make sure your message explicitly states that people will still be able to reach you, and how

As with all winter breaks, but especially in a longer break, division and department leaders are responsible for ensuring that external contacts are aware of the closures and as appropriate salaried staff are performing services as necessary to meet the needs of the community during the closure, including checking email/voicemail and responding to time-sensitive matters.
While this sounds kind of onerous, I don’t think it’s actually a bad idea to say “I don’t have this info but I’ll get back to you when I find out” if it’s going to take a while.