In my (US-based) experience, doctor offices & the like have a place where you can fill out if they can leave messages or not (and some even have asked detailed messages vs callback messages), so that's my perspective! And that I can set different things for different numbers. So my cell phone they can leave detailed messages on any matter, my mother's house phone is detailed from billing only and otherwise callback, her cell phone is callback only. (And they also aren't allowed to tell her anything other than billing, so even if she does call them back about anything else! That was just a measure set up when I lived with her one summer & had no cell reception at her house.)
Creating a voicemail greeting might not be fun, but with the scripts I’ve shared, you should have an easier time. No need to practice time and time again — simply plug in your name, company title, and other details, then read it out loud to your phone’s voicemail greeting recorder. With a professional greeting, you’ll continue nurturing prospects even if you don’t pick up the phone.

If anything big changes- address, phone, etc.- make sure you correct your voicemail early on. Keep It Short; We know, we know. We just gave you all this information and we’re now telling you to ‘keep it short‘. But, a professional voicemail greeting (or any for that matter) shouldn’t go beyond 20-25 seconds.
Most callers expect their call to be answered. Once they realize that your office is currently closed, the most important piece of information they probably want to know is your standard business hours.