The correct answer of course is, "It depends..."
The flies used in this blog are all simple to tie, because this blogger is not what you'd describe as a "skilful fly dresser". They all work well, because there is no point in making flies and carrying them about if they don't!
This little table below might prove helpful to anyone starting out to make themselves their own version of the "Derbyshire Fly Box". Readers from around the world have been very kind in reporting that, on their rivers, these flies do still work and often working very well indeed. It may also make a good starting point for a newcomer to dressing their own flies.
Click it for a closer view.
Of course you will need some hooks and the tools
(Oops!! I've also forgotten to add the materials in for the wings of the PPSG Poly Prop Spent Gnat... Sorry!)