How can you tell? In the range of 99% of people who visit the medical would have been fine without the visit by using a little common sense about their malady. In fact, many of those people were persuaded into some kind of procedure that harmed them more than they would have been helped if they had done nothing. When you consider the millions of people who die under doctors' care, and the $billions of dollars they pay the doctors to die, it's turning out that the enemy is really the medical.
If you're in a private system then this really is something I can't argue with. Overprescription and over attendence seems problematic, I've heard annocdotes of people coming to the UK and Scandinavia and using the socialised services and being surprised when a cold/sore throat is prescribed a hot beverage, a bath and rest. Rather than the US where you're probably at the very least sold antibiotics which will do nothing more than a placebo.
(I can't obviously call any system perfect as none are but some seem better than others in certain aspects). Don't bring up cancer rates though - there is a problem with thinking you can cure everything at home.