I know that the Bach flower remedies are quite powerful; when my Mum was in terrible grief after my Dad's passing (about 6 months later), I took her to someone who tested her and gave her a particular mixture; she could not believe that she was her old self in three days! Prior to my own essences, I used the Rescue Remedy and it worked. I did not test my Mum because I find that when a perfect stranger is helping her, it has more impact! :( Anyway, whatever works! :)
I work with 51 essences from the garden at Perelandra. I should (but do not always) test myself in the morning for any basic essences which I might need. When I do this on a regular basis, life just goes more smoothly.
Of course, the crux of the matter is being able to test yourself. If you go to the site: www.perelandra-ltd.com and click on Education (at the top), then you will see Kinesiology Testing on the sidebar -- click on that and you will find that the whole thing is there for your printing. It is very easy to learn, needs a little practice, but then you can test anything to see if it is good for you.
These are the same essences which I use for the plants in my garden. They come from the various plants at Perelandra which is VERY much in balance. The tomato plants are supported by huge trellis-type boxes and are at least seven feet tall! There is a 'bug alley' which is a long planting of various plants, strictly for sick bugs to recuperate. Total amazing!
Anyway, if you are interested in learning how you can test for your own requirements, take a look over there.