I like to do it 3 times a day, but circumstances have prevented that lately. I still aim for twice a day and hope to be back to 3 times soon. I find the more often I do it, the better the results. My fav is VCO but I also use sesame and sunflower.
My 15 year old son started today. He is only aiming for once a day, but I am thrilled that he was willing to give it a go. He has a dental appointment in a few weeks, so I will be interested to see how he goes.