You're right on the riding a bike, I took a 14 year hiatus to fool with hot rod cars and went back to my passion (airplanes), built a trainer (Goldberg Eagle 63) and flew it unassisted, then flew it on floats then made a tail dragger out of it and etc etc. That was in 88 and now I'm in to WWI scale stuff, the bigger the better, I suppose I've built near a hundred sport types and got the scale bug. I'm 70 in three weeks and a couple of days.
Doc