You can't answer the phone from a roof. Or mid-quote, or in a ceiling cavity, or at your kid's swimming carnival. So the call rings out and goes to voicemail. A caller who hits voicemail often just rings the next name on the list, and somebody else's week just got better.
The maddening part is you never find out. A missed call doesn't send you an invoice for the job you didn't get. It's just quiet — a coin that got tossed and landed while you weren't looking.
Your options have traditionally been: hire someone (a wage for a phone that rings in bursts), let it ring (see above), or divert to an answering service. This page is about the third option — what a phone answering service actually does, what the traditional ones cost, and how Giday's version is different: it doesn't just catch the call, it finishes the job the call was about.