Again, leather watch bands are subject to constant movement and stress.
Being a real material, it will of course break down eventually, but being under essentially no stress, that will likely be in 20+ years at an absolute minimum....
If we want an actual comparison, anyone want to comment on Enterbays 1/4 T2 T800 clean version? That has a full leather outfit.
That is now a couple of years old. I haven't heard of anyone desperately applying leather waxes.....yet
The problem is the leather straps weren't really being worn, the leather pretty much just hardens & become fragile due to non proper storage (just put inside a box), I don't know whether 1/4 T2 T800 uses real leather of pleather, if it's pleather it really depends the type of pleather they use. But if you have confidence with your leather then i don't think it'd be an issue for you. For me i've encountered too many problems with Pleather/Leather so if i can wax them up when new i don't see it as a bad thing to do. For Pleather it might just make them last 1 year longer. What i did for SS Anakin was put some thin coat of paper glue coating on the areas starting to flake/melt.