I am on annual leave until [DD/MM/YY]. I will allow each sender one email and if you send me multiple emails, I will randomly delete your emails until there is only one remaining. Choose wisely.
Here is an auto reply message example that provides an alternative email contact option to assist customers during the absent period. Thus, helping customers not to make impromptu decisions and understand the next course of the move.

Note: Outlook does not attach your signature when it sends automatic replies. If you have a signature, you might want to paste it below your message. If you don’t have one, check out our guide on how to add an email signature in Outlook.
My OOO is almost always “I’m out of the office and will be returning on x date.” My email sig has instructions along the lines of “for questions on x, email this list” for a couple of the more common areas people would contact me about that might need an urgent reply (as the lists go to more than just me, obviously), but most people have finally figured out to contact those lists to start with, anyway. If I were in the middle of a project or something that needed to be moved along in my absence, the project teams usually know when we’re out, but I’d put a back up in that case, if needed, but generally there’s not much to be gained by a longer OOO from me.