The bottom line is that a business’s situation is likely to change often and rapidly, each of which need a unique and applicable voicemail greeting to cover the circumstances and timeline. For example, callers shouldn’t reach a business-as-usual voicemail, and therefore expect a return call within the business day, if the subject they’re calling is out on vacation for two weeks. Such a lack of communication is a recipe to lose that caller’s trust and tarnish the brand’s reputation.
2. It should only take 8 seconds to connect me with your phone, and no longer. So if I have to listen to 15 seconds of your crappy music, it means you’ve prolonged the connection process just to expose me to your musical tastes. How dare you.

So long as phones can ring and eyes can see, leave a message, and I'll get back to thee.
Recording voicemail greetings for your business or personal life requires a separate list of priorities, because they are being used for two distinct purposes and will be heard by two very different types of callers. I have a friend with two cell phones - one for work, and one for personal calls - and if you call both lines, you would never know it's the same person.