I have a confession to make: I haven’t recorded a new voicemail greeting since 2014. In the past four years, I (hopefully) have become more articulate, poised, and self-assured. But hear my voicemail recording, and you’d think I was still new to the work world, a little unsure of myself — and probably not an authority. Obviously I need toupdate it. And if you haven’t changed your voicemail greeting in over a year, you’re likely in the same boat. After all, a professional voicemail recording boosts your credibility, makes you seem more competent, and encourages whoever’s listening to it to continue the relationship. A relatively unprofessional one — like mine, for instance — does the opposite: It encourages prospects, recruiters, and potential connections to run in the other direction. With that in mind, I’ve written 18 unique voicemail greetings for every situation. Pick your favorite, practice a few times, then record your new voicemail.
Since I pride myself in being responsible, if I don’t receive a return call I have to assume I wrote down wrong number. If I were irresponsible I would just blow it off and not care. But if I wrote down the wrong number I have a responsibility to get a hold of this person. This extra work combined with wondering if it’s the right number, leaves a bad taste in my mouth.

If you are going to be unavailable for a predetermined time, let people know. Example, if you are on vacation for the next two weeks, inform your callers in your greeting that you will be returning calls on such and such date. This way they expect it to take a couple of weeks before you get back to them instead of stewing over why you haven't returned their call.
One system and one monthly bill across all your office locations and even your mobile workforce. Admins and users can change their own settings easily, on the fly, from the Web or even from their mobile devices.