Over at The Chronicle, Kevin Dettmar answers a department chair's question--"How do you get professors to respond in the summer?" with some words of wisdom: https://www.chronicle.com/article/ask-the-chair-how-do-you-get-professors-to-respond-in-the-summer. His answer is, basically, "pay them," and it is so good to hear that.
From the piece (behind a paywall, sorry):
For scholars, summers represent what the weeks between Thanksgiving and Christmas are to the retail trade: the time when we move, if barely, from the red into the black for the year’s writing and scholarship. And as someone who has tried to remain productive, I guard that time jealously — no, viciously. So I’m in full sympathy with your faculty colleagues, as perhaps you are as well.
Other good advice: "plan ahead" and "show them the money."
But I needed the reminder that Dettmar provides and that I wrote about in 2018 to push me into applying this principle to another time-sucking practice, not from university departments but from faculty who are heading off for three weeks on a fabulous research grant or vacation and will eat up all your time on either side of their time away by impinging on your time with a flurry of emails and requests, especially if you haven't set a firm boundary.
You don't have to have a fabulous grant, or a destination further than your own back yard, to ignore these requests. As Dettmar says about department chairs, their timetable is not your problem, and you don't need to make it your problem to be accommodating.
An example: in Herman Wouk's Marjorie Morningstar, the mother tells Majorie, who's working for free at a summer camp, something like "they can wait for a while for what they're paying you." It's not always true, but it's worth keeping in mind.
Maybe this isn't a problem for you, or you have a scorched-earth out-of-office message doing that work already. But if you don't--if you're inclined, like me, to respond too quickly and be too accommodating--this is a reminder that you're paying yourself to write or research or relax this summer, and that anything work-related that interrupts might be able to wait a while, for what they're paying you.