I got a new cell phone recently. As the world stood in line to pick up the latest iPhone 8, I graduated to the 6S. I pride myself on that actually. As with all new phones in the 21st century, the voicemail must be set up anew. I used the default message for the first few days, but finally settled down to record a more personal greeting.
Obviously, I need to update it. And if you haven't changed your voicemail greeting in over a year, you're likely in the same boat.

With Apple Visual Voicemail, the red circle on the phone icon on the main menu changes to an indication of how many new voicemail messages you have received and how many calls you have missed.
Voicemails have been around in one form or another since the beginning telephone communications. This feature still manages to make its way on every smartphone, despite the rate in which technology is evolving. The reason for this is usefulness – you won’t miss any unanswered calls even if your phone is off. The voice messages from your callers will be transferred to your voicemail box and you’ll be able to listen to them at a later date.