This isn’t intended to be the final word on voice mail etiquette, but it is my take on it. I need to say as a bit of a preamble that I don’t think one has to answer the phone just because it is ringing. The timing may be right for the person calling, but not for the person being called.
So, here is how I operate and I welcome your feedback:
I call a friend and leave a message. It’s great if they can get back to me by the next day but there are no strings attached. I hope they feel the same way when they leave a message for me.
I call a friend asking for a favour. If they don’t call back, no problem. If a friend calls me asking for a favour and I don’t call back, it’s because I don’t to do you that favour. I would prefer that you don’t keep calling me but I would admire your persistence if you did. I don’t love helping friends move for instance and coincidentally those are the times I seem to have trouble with my voice mail.
In the area of business calls I would say to return a call as soon as possible or within 24 hours, depending on the urgency. I think it goes both ways here.
In the area of business favours, if I call you asking for a favour, it’s up to me to keep trying to reach you. It is not your responsibility to call me back; however if you do, that would be cool.
And finally, in relationships and from recent personal experience, if a girl doesn’t return your call after 10 days, she probably isn’t into you, or in this case, me.