In the old days, what you have offered is what neighbors would do.

Illinois Law says for both persons to go to the fence on their property and face each other at the middle, the half on each person's right is their responsibility.

Back when neighbors were neighbors, often if someone didn't want to provide labor, they would buy the fence, and the other neighbor would build it.

Then, many people who didn't have cattle didn't feel as if they should have to do anything.

My FIL built all the fence on a quarter mile when the other neighbor didn't want to do the labor, but had cattle and furnished the material.  The neighbor had cattle against that fence twice in 40 years, plus the brush grew back into the fencerow after it had been cleared.  FIL didn't use his half of the fence, but felt obligated to do his part for the neighbor.

Yes, you have an excellent deal, but more important than that, an excellent neighbor!

I would do most anything to accommodate a neighbor that was cooperative as yours, fortunately all of mine are excellent, but I have heard some horror stories about a few uncooperative people.

If I had the choice of thousands of dollars or excellent neighbors, I would take the excellent neighbors anytime, they are a precious commodity that is getting harder and harder to find.

In fact, I have often spent many dollars I really wasn't responsible for, just to keep those good neighbors happy.