I use a 50/39/30. I hardly ever use the 30 and rarely use the 39. I ride the big chainring most of the time even when climbing. I have a 9 speed cassette and generally only use the 15 or 17. The only reason I had to replace the cassette a couple of weeks ago was because those two gears were worn enough the chain just kept skipping when on those gears. I ride single speed most of the time while on a a trip and only change gears for a mid Appalachians style climb(3-4 mile, 300-400 feet per mile).