Stethoscopes

Why do doctors always have stethoscopes with them? I can see if they are attending to a patient then they might need it – but at other times, is it really necessary? Any time I see doctors in hospitals, or on the show ER, they always have stethoscopes. In the last few times I’ve been to the doctor, he has not had to use his stethoscope for me. How many hearts are they listening to? Is that the first thing that needs to be done with any patient – listen to the heart? I really don’t know about this since I’m not a doctor, but I would think the fancy flashlight would be just as important. Perhaps a tool belt is in order for doctors so that they can carry their arsenal of tongue depressors and cotton swabs. Why should the stethoscope get priority?