I like what Kioki says about daily driven vehicles not needing a cleaning such as the collector cars or bikes that sit for long periods of not running. But then he hit on a key point about vulcanization of the "O" rings after 15 to 20 years of use. When the rubber get hard, fuels gets by it and causes other issues.
Kioki talked about the ethanol issue to but maybe not as much as he could have and how that effects the rubber used in many engines. Thanks
@Kevin frazier