Personally, I seldom bother with adding any sort of cement to the base layers of flies I tie. Occasionally if I'm tying something for bluefish, pike or other fish that'll destroy a fly in the blink of an eye I'll add head cement or flexament to base layers, under any point where I've tied something in and any other spots that I can identify as potential weak points. Normally, if I'm not fishing for anything unusually toothy, and if I'm not overly concerned about the fly being of industrial strength, I don't bother.
I guess it makes sense that people writing a knot book and showing you how to tie flies would be proportionally more interested in creating flies built like steel than the ordinary fisherman. Like I said, its probably a good idea to do it, but when weighing the time it would take against the benefits of having it done, its really just another step that I don't take unless the species warrants it. John Roth
