annual physicals?

I think we hear the advice that you should visit your physician every year and have a physical.

I admit I am guilty of not having had one for probably more than 7 years.

If I get sick, or if something doesn't work the way it's supposed to, I go see a doctor. But I don't have a primary care physician that I go to.

My question is: how important is it to get an annual check up? You know - to check all of the fluids, make sure they are clean and at the right level, make sure the belts and brakes and tires don't need to be replaced - that sort of thing. And at what age, for men and women, does this become important? Likewise, through what age is it important to ensure children have regular check ups?

Thanks,
maverick