There are few things in life that are foolproof combinations. Salt + Pepper, foolproof. Oil + Vinegar, foolproof. We don't always have time to figure out what goes well with others and risk is involved when combining two things for the first time. At best, failed dinners, at worst...well, there are a lot of 'worsts'. At least with scents, Demeter makes blending easy with their Foolproof Blending Kits*.