When I lived in North Carolina a number of years ago, I use to drive over the border three times a week to Muzak headquarters in Ft. Mill, South Carolina and voice countless on hold messages. (Yes, Muzak does a lot more than just produce elevator music.) I was one of many voice talents who would drop in throughout the week to voice from a VO booth. We had an audio engineer down the hallway who would roll scripts on a monitor in front of us and capture the on hold messages for editing and formatting later. As voice talents, our role was to come in and voice as many two-three paragraph scripts as we could in an hour. This required very good "cold reading" ability. That is to say, we didn't have a chance to see the scripts before the session, so you had to be good at voicing on the fly. If you made a mistake, you'd simply revoice the line and move on-the fix would be done in editing. There was a HUGE premium put on voice talents who could whiz through the scripts and voice say, 35-45 separate messages in an hour. We were paid a decent hourly rate and the work was relatively stress free with nominal direction. I did the math once and know with certainty that I have voiced literally thousands of on hold messages in my career.
Phrases like, "You're call is important to us," "Thanks for holding...we'll be with you in a minute," and "While you're waiting, did you know...?" have been the norm for many years with little change. Of course, many folks hate to be put on hold or get caught up in an on hold hell of sorts as they feverishly push buttons to be connected to a live, breathing, human being.
I've had a few funny experiences over the years when calling businesses. Recently, here in California, I called an online auto parts supplier to follow up on an order I had placed through their website. It was very early morning and I received an hours of operation, on hold message. ("We're currently closed, but our hours of operation are from..."). I heard the voice and thought, "Boy, that guy sounds a lot like me," when it dawned on me it WAS me! Having voiced so many on hold messages it's easy to lose track and some can run for quite a while before needing to be updated.
Another time, a producer/client friend of mine emailed to tell me he was with friends in the middle of a California desert getting some gas when he heard my voice overhead at the gas pump beckoning customers to come in the convenience store to get a Slurpy or cup of freshly brewed coffee. He said it kind of freaked him out as my voice came out of nowhere and he told his friends, "Hey, that's John Miles. I hired him to voice for me." This type of messaging is what is known as "overhead." You hear these messages in stores all the time.
I still voice on hold messages for a Long Beach, California producer and a few others, but not to the extent I did while voicing at Muzak. Many voice talents stay away from on hold work. I still enjoy it. Part of the challenge is to combine a conversational read with some enthusiasm without sounding cheesy.