ember - 4:23 pm on Oct 21, 2013 (gmt 0)
I've found that generally Google knows what it is doing (not always but most of the time). They have way more experience and data than I ever will. They say to let everything run because it will increase competition among advertisers and increase bids and my revenue. That concept works for me. When I've tried to be clever by turning off image ads or enhanced ads or whatever, my earnings suffer.