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.
You don’t have to spell out every single thing that you think they might want to know. Have some faith that your callers will be able to figure things out on their own. Be natural but informative.

The answering machine, answerphone or message machine, also known as telephone messaging machine (or TAM) in the UK and some Commonwealth countries, ansaphone or ansafone (from a trade name), or telephone answering device (TAD), is used for answering telephones and recording callers' messages .If a phone rings a number of times predetermined by the phone's owner, and nobody is present to answer ...
2. Mention Hours of Operation Upfront. 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.