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.
Another point you want to bring up in the first few seconds of your call is why the person should keep on listening.

Don' let background noise do the talking for you. Ambient noise on your recording could be sending the wrong message to your clients. The sound of your kids arguing in the distance could be the sign of a distracting work environment. Clinking glasses and restaurant chatter may leave the impression that you don't take your work seriously. When you record your voicemail greeting choose a quiet spot free from interruption, so your message is the only thing callers hear. It's also good to avoid large, cavernous spaces where sound verberates.
Generally, people that call and leave messages are more likely to be ideal customers of your business. Your voicemail message is often not much more than a formality to the person calling.