This maple is not looking so good. It is about 30 years young but needs a good pruning as the grass beneath it is all... well... dirt. I saw this nice sized chunk starting to rot filled with bugs. About 7' up before the main split. Firewood or let nature take its course?
I would take it down if it is anywhere where you walk. That spot is just itching for a big wind to come along and snap it off. If you can use the wood, take it down on your terms. Never know what you will be left with if you wait for it to die or rot more.
If you wait for a maple to "self prune" the grass will never grow under it. Proper pruning will make for a healthier tree and may open the canopy enough for shade tolerant grass to grow under it.
Nahhhh, the rotten hole near my hand is below the main split. Nature taking its course was to say let it die over the years versus felling it early fall. Either way it will get pruned... one a bit more so than the other.
Ants can hollow out a maple pretty quick. They're eating your firewood! I'd say take it down before it becomes a limb dropping hazard.