I OP on average once per day and usually not until mid-day when my girls are napping, or late at night when they are sleeping. I definitely can tell a difference when I increase frequency and try to do it more often when the pollen count is high, especially. In a perfect world I'd OP when I woke up on an empty stomach, then again before dinner or bed...but that probably won't take place soon! For now, I still feel that it is a great therapy even though I don't do it first thing and I have usually eaten or at least have had my morning coffee...I look forward to the day when I can really follow the protocol!
And I really notice when I don't OP for a few days. I am away from home now and skipped a couple of days and my head starts to get stuffy and my skin broke out.