For about ten years before I got a new road bike last spring, I'd been riding around on a crummy $100 mountain bike from Costco.
For Nondenominational Winter Holiday my girlfriend bought me a bike consultation at Shaw's Lightweight Cycles. I had my riding posture/technique evaluated and some small adjustments made to my bike. I would almost compare the experience to being taught to ride a bicycle anew. It seems to be time and money well spent.