Most companies selling essential oils do beginners kits with anything from ten to twenty oils and I would probably not need more than twenty for ninety per cent of my clients. It is only for the other ten percent I actually need to have more.
However, I can even for the ninety percent of my clients achieve better outcomes by tweaking the oils. For psychological issues which means most of my clients, while Bitter Orange and Bergamot might have very similar therapeutic properties, if they prefer one over the other it is likely to be more effective and they are more likely to use it regularly between sessions if I give them some in a carrier oil to take away.
I have two different Frankincense varieties, one, from Brazil has a greener aroma than the Somalian one which is drier. (Green and dry are terms used in the perfume industry to describe aromas.)
There are many other essential oils where it is useful to have two or even three varieties in my tool kit and there are many essential oils that I find use of is seasonal. There are a number of oils I use more of in the winter for those struggling with respiratory problems. At the same time oils that are cooling in nature I use more of in the summer.
Because of this, I have around sixty different essential oils, some bought only in five ml or even two and a half ml bottles if they are ones I don’t use a lot of.
In the unlikely event that I feel a client needs an essential oil not in my tool kit, I will buy it as inevitably it will be useful with other clients at some point.