Yeah, announcing you were going to delete emails unread and expecting the sender to resend when you return would NEVER fly in my office. I’d get executive complaints about that, especially if it went to a client or outside party – if a client can’t reach you, they will reach out to someone else who may not work at your organization and you lose business. I feel like this delete-it-all philosophy would only work for an entirely internal role where timelines are more relaxed, and even then, I feel it’s a bit unprofessional to foist your own catch-up work onto others, especially if they’ve been backfilling for you while you were OOO.
You might receive multiple emails from coworkers and clients if you’re not specific about your absence dates, which will clog your inbox and make it hard for you to remain productive when you get back.

Once you’ve finally crossed off those last-minute items on your to-do list and are ready to check out of work mode for while, there’s just one last thing you need to do – set your out-of-office message.
“For example, if a hacker knows that the chief financial officer of a company is OOO, thanks to the information in the auto-reply message, an attacker could impersonate the CFO on email and target another individual in the company’s finance team asking them to make a payment or update bank details for them while they are offline,” says Sadler.