With so many skincare products out there to layer on and keep track of day vs. night, it becomes overwhelming very quickly. If you have to add just one extra product to your skincare routine, we'd have to vote adding a serum. This doesn't mean your regime becomes more complicated but, instead, more clear as to why these skincare powerhouse products are necessary for every "lazy girl" out there. Here are out top picks of face serums for mature skin, oily skin, sensitive skin and every other skin in between.