Some people may have multiple phone numbers. The reason I give multiple numbers to select people is this is the number I am likely to call from. However, when calling me – the best number to reach me is +1 412 253 2956. This number is a smart forwarding number, and will forward to one or more telephones. If you were to call another number, it will only ring that number.
Note, if you are an international user, it might make more sense for you to call either my South African or UK number. In which case, no matter which of these two numbers you will call – it will ring a SIP account on my smartphone.