If you have an old, glorious ash tree in your yard, what should you do? With the emerald ash borer on the move, doing nothing is not an option. You need to either remove it or treat it.
If the tree would not cause damage if it fell, try to treat it. It will cost you about $300 every two years. But treatment over a long period is not sustainable. If you are not willing or able to make that commitment, I suggest removing the tree now.