I usually don't address anyone by name. Many times it is because I can't remember their name. I do however rember my T and Pdoc's names. However, I have no idea how to pronounce my Pdoc's first name so I'd never call him by it.
When I leave messages for my T there is no reason to specify who he is because it is his own personal voice mail. If I called my Pdoc's I would get a receptionist and have to specify which Dr. so I would use the title Doc. but I have never adressed either doc with a name.
When I'm talking to my husband I'll say Dr., or first name, or sometimes I'll say T or Pdoc