In the beauty world, there is probably nothing more divisive than the use of oils, essential oils especially. Some swear by oils for healthy, moisturized skin; others insist oil-based products cause breakouts. Unfortunately, getting to the truth isn’t all that easy — as with most beauty-related concerns, determining if oils work for you is often a matter of trial and error. But, skincare errors? Not so fun. So we decided to get to the bottom of the oil debate once and for all, and consulted Oille owner and clinical aromatherapist Kirsten King to get the full (and, as it turns out, fascinating) scoop on oils — from the essential variety (think: calming lavender), to carrier oils (think: olive and sweet almond) and everything in between. As it turns out, pretty much everyone — save, occasionally, for pregnant women and young children — can benefit from a boost of oil. The trick is finding which ones work for you, because like any skin product, different types have different functions. Ahead, everything you need to know about oils for the best skin of your life.