My busn # has been my cell # since 95. I moved and back then you couldn't take your # with you if you moved into a different area. I had 4000 busn cards out there, all with the wrong phone #. So I decided to just use my cell# since it was a local call for anyone in the area but a local# would have been a long distance call from the peninsula.
If the network went down, they can always leave a message, which can be retrieved from any phone. When I'm traveling customers can call my # and it will ring wherever I am in Canada or the US, just like normal. They have no idea I am in Nashville or Toronto. I book the job and keep going.
Nice thing about the new regulations is that I can now keep my cell# if I decide to change carriers.