The 35mm Q - worth having both 35L and 16-35L?

Generally, very few zoom lenses are at their strongest at either end of the zoom range, so having a prime lens that matches the focal length at either end of the zoom's range is not, in my opinion, excessive duplication. Moreover, good primes will be more useful in lower light.

Buying my 5Ds R in January 2016, I figured I would upgrade some lenses. I traded my 35L, while planning to eventually add a 35L II. Part of the long-range strategy was to acquire a 35IS, because I see the 35IS and 35L II as being distinctly different lenses, suited to differing roles. I soon bought the 35IS, and really do like it. I will admit that there are moments I really do regret trading my 35L.

Then, a friend, who works at a local camera store, tempted me to try a Nikkor 35/1.4G on my D3s. Pixel-peepers love to hate this lens, but the overall image is more important to me, and this lens has become a favorite on my D3s, this combination now being my "weapon of choice" in very low light. Buying this 35/1.4G has certainly delayed my acquisition of  35L II, but perhaps in 2017 or 2018, I can justify adding a 35L II, to use on my 5Ds R. I use my D3s and 5Ds R for completely different types of shooting.

I traded my 16-35/2.8L II, toward the above-mention 35/1.4G, with the intention of eventually adding a 16-35/4L, or perhaps the rumored 16-35/2.8L III. There is no hurry, for the UWA, as I also shoot 7D and 7D Mark II cameras, and my EF-S 10-22mm is really quite good; so good, that I sometimes question my real need for a 16-35mm lens to use on "full-frame" cameras. The 16-35L IS, obviously, has better environmental sealing than any EF-S lens, so a future trip to a dusty area may be what finally prompts me to add a 16-35L IS.