I can't fish without a nylon or fluoro leader. Without it, the braided line gets exposed to attrition with rocks, logs... Fishes with abrasive mouths, like snooks, simply obliterate braided lines. And they tend to get coiled in the treble hooks too.
I tie them using modified Alberto knot. You pass the line two or three times inside the knot eyelet, instead of one, like in the classical knot.