Vitamins come from fruits and vegetables, so I believe unless you have specific dietary needs, if you are eating a wide variety of fresh fruits and vegetables you are probably getting the vitamins your body needs. Many vitamin supplements are poorly made and contain a lot of fillers so you don't really know what you're actually getting.
I found a very noticable benefit from eating vegetables. I recently increased my vegetable intake considerably. Most are fresh or sometimes frozen vegetables. After about a month, many of my aches and pains are gone. I never saw a doctor about these aches and pains but just considered them to be old age setting in.