I'm here about 7 years and I've had tree guys in three times as a result of storms knocking a few branches off this maple. If in the photo below you could imagine the tree being symmetrical rather than bare on the left side ... that's the way the tree was 7 years ago. My neighbor has been very patient with me, since the limbs (one of which was about 12" in diameter) always fall in her yard (which is landscaped like a tennis court ... lol.) Luckily there's been little or no damage and no structures in danger.

Other than age, I think the culprits are carpenter ants. The photo below shows a hole at about 5' above ground. The hole measures about 15" across, about 24"high and about 8-12" deep. There is exposed wood, ants, and tunnels and channels. Is there anything I can do to prevent further damage, or to structurally repair this damage.