Like most American anglers, I have always attached the standard 9-foot (sometimes 7.5-foot) leader straight from the package to my fly line, added a foot or two of tippet material, and set off on my merry way. And that's always worked. But it's amazing what adding just a few more feet of tippet, so that you're ultimately casting 15 feet or more of clear material, can do for your hookup ratio. It eliminates fish being spooked by the solid fly line (of any color) directly overhead. It gives you a longer drift through the zone, and it eliminates much of the drag as you present the fly—all really important keys to getting a spooky, selective trout to nab a dry fly off the surface.