I just graduated medical school, so I have at least some authority on the subject, but I plead with people to go to the doctor at least every 3-5 years even if you never get sick. If you have even a halfway competent family doctor he will know what tests and exams to perform so that he can detect things that when things get serious, it isn't too late. For example, if you wait until you pass out from a diabetic coma, you're already well into diabetes, where instead if you have some minor symptoms and are found to have insulin resistance you can make some dietary changes so that you never have diabetes. If you have moderately elevated high blood pressure (but don't know about it because you never went to the doctor) you are putting undue stress on your organs. There are dozens of similar problems that most people shrug off as nothing but when taken together can point to a potential serious problem or complication.
However, like the poster below mentioned, if you have the common cold or even influenza just stay home so you don't infect everyone you come into contact with. The likelihood that you will come and see me in time for tamiflu to do anything is pretty small, and I'm not really convinced it makes much difference anyways.