I oil pull twice a day...morning and night. Do I need to put the oil under a microscope to know that it's working? No, I just know it's a good thing. If nothing else, it removes ALL the plaque from my teeth and my mouth just feels so good after I finish oil pulling.
I used several different kinds of oil before I settled on coconut oil. I keep it in my bathroom and use it in the morning when I shower and at night when I take my bath. It's become such a part of my routine, I don't feel "dressed" without it.