I can not imagine anything other than tippet material, leaders, floatant, light bulbs and batteries that I really need to buy over the next 20 years to keep me fly fishing and tying. I have enough books to read, materials, hooks and tools to tie with and rods, reels and lines to fish with to last me a lifetime ...not to mention several sets of waders, shoes and hip boots. Unless some new indestructable float-forever fly line comes out I am happy with what I now have in my possession. Other than the above mentioned I have no need to buy another thing....but I know I will...
On a personal level, not commercial, how about you?