The length of your fly leader depends a lot on your trolling speed. A shorter leader will whip faster. 22 inches is the industry standard. If you tend to run slow...like 2.0 at the ball a shorter lead might be better. I tend to run a touch hotter than most. My leaders are 22-27 inches. I have a few tied up short that have never taken a hit. But I guess it all goes on what works for you and your program.