The biggest reason I have stayed with the same primary doctor so many years is the relationship I have built with her.
I don't have to go through my entire history each time I go to the doctor. If I need an antibiotic for a urinary tract infection, or strep throat, it is a quick appointment.
All of my records and medical history are in one place. I know some people who don't really have a family doctor and just use a walk-in clinic when they need to be seen.
Their records are scattered all over the place, and one doctor never gets to see the whole picture.
I like the idea of building a relationship with my doctor. This is something I feel more comfortable with, and feel confident knowing I am getting the best care.