I currently live on a small bay at sea level that requires a 2 miles stint at 7% grade in either direction unless I take the back road out of town and that is 12% and almost 3 miles. I used to live in the mountains at 6500 foot elevation, that tires you even before you start to climb haha. On my modern bike i can climb most hills in the saddle, but on the vintage bike I'm slowly climbing stairs. Since I ride purely for the workout though, I have really come to like hills and the slower pace that they force upon you (half the time)