DEAR HARRIETTE: I have had a land-line for my business for more than 20 years, but I hardly ever use it anymore. I have been looking for ways to cut costs, and I had the thought that I should just make my cellphone my primary number. Most of the calls that I get on voicemail are solicitors anyway, so I don’t think I will miss too much business. I’m a little nervous, though, since I have had my num…