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:
A literary agent I follow told the story of a long argument her autoreply had with a would-be author. She’d set up the outbound email while out of town and apparently an author who queried her with his book took offense to it. He replied back in frustration that he didn’t get a personal response. Her autoreply sent back another automated message, which he then in increasing anger kept responding to.

Be aware of your tone. Keep it clean and simple. Sullivan says: “Even if you work in a casual office environment, the people emailing you may not. It's fine to have a light tone in your communications, especially when you're in an email conversation with someone directly, but your OOO is more of a blast message—including a cat meme or silly quote could backfire if your OOO goes to, say, a new client prospect or the sales director at a company you've been trying to engage.”
I’ll be unreachable for a few days starting on December 11th because I’ll be at Growth Marketing Conference. I’ll have limited ability to return phone calls and emails until I return on December 13th, but if you want to talk accounting software options or learn all about the latest growth marketing tactics and tips when I return, please shoot me an email. I’ll get back to you as soon as possible. If you need immediate assistance, please contact my assistant Megan White at 971-841-0098, or at [email protected].