DW,
Each of us has reasons why we include or exclude inspection rings in certain places. There are a few thoughts people consider with this. 1) Inspection rings are really, really cheap 2) They are real easy to put in during the process of covering and likely to injure one's religion if missed and needed later 3) Don't have to cut the hole unless needed later.
For sure, internal moving parts and access to fasteners is important. After working on some old piper tube and fabric airplanes, it became apparent to me that long term a person might want access to additional areas for the purpose of inspection (corrosion/dropped a wrench down there/bird found the airplane good for a nest/busted pitot plumbing/etc)
So, ended up installing rings in 6 bays in the wing, excluding the outboard bay and the two the fuel tank occupied. Also made an access point for the finger strainers like Jim mentioned - this would be a bearcat if a person could not get into that point; although I went with a rectangular fabricated aluminum cover instead of an inspection ring.
On the other hand, early kitfoxes called for even permanently attaching the wing tip including covering over the seam.
All depends on what a person thinks about what they might run into in the future.