Jeff--
As far as i can tell--my Silver Maple (PLANTED IN 1972) is doing OK.
May be because, for years, I had lawn service, which also fed the tree roots.
I have never had it checked by an Arborist (how much do they charge???)
but the limb-structure looks solid. No narrow "V"-shaped crotches.
Even with that--I would not mind removing one of the main limbs which
are, mostly, over my neighbor's yard. It would not alter the shape of my maple-- as it will still have 3 or 4 strong limbs on the tree.
To me--it looks like a strong, solid tree. Not countilg all the small branches
that come down regularly in heavy rains and winds.
I just call it "Nature pruning" my trees.
Here are 2 pictures of the big. old S.Maple in my back yard. I have other pics. but fon't have tome to hunt for them. The trunk I am referring to--as leaning over my neighbor's yard, is on the right.