If you're a healthy, active adult eating a well-balanced meal including fruits, vegetables, high quality proteins, and healthy fats, you probably don't need a multivitamin. However, if your diet is restricted, if you're vegan or vegetarian, a pregnant or nursing mother, you probably want to think about taking a multivitamin as a supplement. If you lead a hectic lifestyle, say you travel a lot for work and just can't get a lot of fresh, healthy foods where you go, if you're eating a lot of processed, refined foods, then you also may want to consider taking a multivitamin as a supplement. That way you're going to get the nutrients and energy you need to keep you going. If you do choose to take a multivitamin, just make sure you buy a high quality, natural brand over a synthetic brand. That way you won't get all the added colorings, bindings, or fillers. Also, with some of the cheaper, synthetic brands, they haven't been tested as much for potency or purity so, again, just make sure you get high quality, natural brands when you're choosing a multivitamin.