"Crank Ad Balance to show only the best ads" — usually wrong

"Crank Ad Balance to show only the best ads" — usually wrong
Ad Balance lets you show fewer, higher-value ads. Sounds smart. People set it to 70% thinking "premium only."
What actually happens: you throw away the long tail of the auction. Those 'low-value' impressions still ADD revenue — removing 30% of impressions rarely raises the remaining CPC enough to compensate.
I ran Ad Balance at 60%, revenue dropped 18%, RPM barely ticked up. Net loss.
Use it surgically for UX on a few pages, not as a revenue lever.
Leave it at 100% unless you've got a measured reason. Steal it.