Of course, your phone rang because someone wanted to get in touch. They got your voicemail because you were busy or just not there. If you section off a block of your day to check voicemails, let the caller know so they can expect a time for you to return their call. People will leave more details if they know someone will check it later.
When creating your after-hours business voicemail greeting or auto-attendant, be sure to explain the hours your business is typically open and any potential conflicts with that schedule (like upcoming holidays or business closures). If your business could benefit from more than one menu option or message use an auto attendant.

37. You have reached [your name] at [your company]. Thank you for calling. Please leave your name, number and a message, and I will get right back to you.
It is important that the voicemail greeting be brief but also action oriented. Do you want your caller to leave you a message? Or perhaps they should call another extension to reach an assistant or office manager in your absence? Get to know the business phone system that you are using and take advantage of its features. Some phone systems allow the caller to press a digit, such as 0 to transfer to another extension rather than having to end the call and dial another extension. This type of function can be extremely useful, especially if other people in the office can handle the calls that are incoming to your phone while you are away from your desk, or out of the office.