I rode for years before I tried clipless, but that was just pure chance. I would think that once riding is pretty much automated so that you gear, brake etc without really thinking, that's a good time to try clipless. I learn best when I have enough "space in my head" to practice only one thing.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett