Thieves oil gets used more often than any other oil in our house. It was one of my least favourite smelling ones when I first got my starter kit, but once I saw how much it helped with coughs and colds I actually started liking the smell. And now it gets put in the diffuser anytime my hubby or I feel like we might be getting a cold. We also have a rollerball with carrier oil and thieves that gets put on our feet anytime we feel a little under the weather. It really seems to help both of us. It is one of the oils in the starter kit, and one of the oils I’ve purchased most often since because it gets used so often.