My family uses essential oils all of the time, for all kinds of reasons. The biggest reasons or most common reasons are for immune health, sinus and breathing, and sleep assistance. I ordered this kit over two and a half years ago, and surprisingly, we still have a little left of each oil, and they are still all good and have not turned bad/rancid. The bottle sizes are perfect and they fit well inside of the storage container I use to carry all of my oils. When one of us starts feeling down and a bit under the weather, we immediately start a daily regiment of using each of these oils, and we feel confident that they have performed just as well as our other more popular branded oils. We love the smells, the thought-out combination of the oils in this kit, and especially the price. The oils appear to be of a high quality and are not diluted. My favorite is the Sinus oil, which I keep a bottle of with me all the time. I highly recommend these oils and specifically, this kit by Pranarom. Two thumbs up!