Training aids: useful and relevant, or dust in the garage

Almost all of us have bought a training aid with excitement, only to watch it gather dust a month later. The industry makes billions promising magic. A good aid only earns its place if it passes two filters. One: it's engaging —easy to set up, with just the right challenge, neither boring nor impossible—. Two: it's relevant to YOUR swing; many force one specific position that may do you more harm than good (for a slow swing, say, a shaft-lean aid can strip too much distance). Advice: don't collect them like swing tips, and distrust the infomercials.