this is why voicemail was invented
In my office, there is one main number that rings to any of 7 lines. There are 8 of us in the office, and whoever isn’t in the middle of another call or an interview grabs the phone as he or she is able. There’s no administrative assistant or receptionist to screen calls.
So when I tell you that the person you’re calling isn’t available and offer their voicemail, don’t just tell me you’ll call again in an hour. It’s our job to be on the phone or in interviews pretty much all day, so there’s a good chance that when you call back, the person you want still won’t be available, and you’ll just have interrupted someone else’s day only to find out that the person you’d like to reach still can’t talk to you. And you’ll just keep doing it over and over, when the person you’re calling could have just returned a call after you left a message in voicemail.
Similarly, don’t refuse to leave a voicemail and ask me to leave a note instead. If you aren’t willing to leave a voicemail, but expect me to interrupt what I was doing to get up and go leave a note on someone’s desk, this is what that note will say:
John Smith called. He thinks he’s too good to leave voicemails.