Yes, to avoid infection and clotting, an accessed port is supposed to be changed at least once a week.
With our son, we don't allow anyone else to access his port. If medical personnel needed to access it, we would access it for them. You have a much higher chance of being more meticulous than someone who isn't emotionally invested in preventing infection.
In our case, we can't leave him accessed constantly. He'll require twice weekly infusions for the rest of his life. We just access twice a week.