An out of office message is basically a quality of life feature both for you and your business contacts. By warning your clients that you won’t be able to reply to their message right away you save the time they might have wasted on follow ups. You also won’t lose prospects who might’ve believed that you’re ignoring their request otherwise.
This is too much. If someone said something like “I’m at the beach until Jan 5!” instead of “I’m out of the office until Jan 5,” I’d appreciate the slight personal touch. But don’t share too much. We just need to know that you’re not gonna answer our email for a while.

What we need in our work communication is not more professional politeness or less formal, chat-based messaging applications like Slack. We need honesty. The problem is that we’ve conditioned ourselves to see honesty as self-indulgent or disrespectful. I’d argue the opposite is true. Honesty, even if it’s a bit more inconvenient for all parties in the moment, pays dividends later. It builds trust. When my partner Anne Helen Petersen and I were interviewing people for our forthcoming book on remote work, a frequent lament from both middle managers and workers was that they didn’t feel like they knew how to succeed in their jobs; that they were guessing what their superiors and coworkers wanted and, even when they asked, they didn’t quite trust the responses they got back.
As long as you’ve covered the basics—dates of your absence and who to contact in your absence—you should be good to go.