Whether one should use a tapered or level line de-
pends on his style of fishing. If he uses his bass tackle for trout fishing (which I guess most of us do) and he casts a floating fly for the spotted princes of our colder waters, he should, by all means, use a tapered line. If he uses only a wet or sunken fly or fishes for bass exclusively, a level line is recommended.
A compromise is the single tapered line enabling the angler to use the tapered end for dry fly fishing and the level end for wet flies, for casting in a high wind or for bass.
Naturally a tapered line eventually ends up level from the weakened part being snipped off from time to time.