As a general rule, people don't need multivitamins, since they are supposed to get all their nutrients and vitamins from the food they eat. However, these days few people have a healthy and well balanced diet, and the food sold these days is not as good either, so there is a real need for vitamin supplementation. However, this should be taken with a grain of salt and not taken to the extremes. You will not notice anything in particular when you take your vitamins, but they will definitely be beneficial for you, so if you have the chance to take them on a regular basis, it would be best to do so. I personally either use N2Guard or Ruthless 3D year round, and feel very well by knowing that my body is not missing anything.