You’ll have options to set a “first day” and “last day,” or just “first day.” If you want things truly automated, picking a “last day” will trigger the autoresponder to automatically turn itself off the day after the selected date. Of course, in those instances when you’re unsure of your exact return date, it’s best to leave this open-ended. The “out of office” subject line is much less creative and scientific than say, a cold email subject line or a marketing email subject line. More often than not, they’re very plain and simple, like the following:
But let’s talk out-of-office messages: overshares, excessive detail, the ones that self-aggrandize (I once had a coworker whose auto-replies often said he’d be in late because he “pulled an all-nighter” on various work projects, etc.), the ones that never get turned off, people who don’t use them at all, and other pet peeves.

Eh, my team’s instruction to put them up if they’re going to be away from email/voicemail for more than an hour (standard lunch break). I have a ton of staff, and we’re in a business where a high degree of responsiveness, especially during the business day, is expected and few of my staff have mobile email. We’re also a larger organization with mixed project teams, and not everyone knows who’s PT/FT or on nonstandard hours.
Because I used to get phone calls that defaulted to, “I need the director”, I had my out of office mail set to: