When we moved in our first floor furnace came with a drip cup for the circulating pump. Now, over 10 years later, we decided the drip had accellerated enough to get it replaced. Our plumbers were fast, though we could hear things like "WOAH!" and "that's not good" through the floor. Now we have a pump which is half the size of the old one and doesn't need to be oiled yearly. I think we did a good job of balancing replacing it right away and not waiting until we had a serious problem.