We have two chimneys in our house, and when we did our extensive remodel we found one chimney needed some work but it was not in the budget. We are about to do the work now.
Nobody really knows why, but there's no sign that the chimney has ever been capped. It has four flues - one for each of three fireplaces, and a fourth was the vent for the old gas boiler; the fourth flue is no longer in use. We are told that the flues are in great shape - or at least they were, but in heavy rain we get water coming into these three fireplaces. I'm not quite sure where the water from the old boiler flue goes. Anyways, we could just put a cheap galvanized cap up, but both chimneys are brick and the one with the cap has a nice brick cap on it which I think we ought to match. The brick in the "bad" chimney is also a little beat up at the top, so the top few rows of masonry need to be redone or replaced. So I need to pay someone to go up on our slate roof without breaking roof tiles, redo a couple courses of brick, and add a masonry cap as well. With a cheap cap, the quote is $2 grand.
This is gonna be fun.