I've been in my house for over three years now. It appears that about 13 years ago, someone bought this house, did a lot of work on it, and sold it in short order - i.e. flipping it.
How do I know 13 years? Because the furnace was 13 years old when it died. Someone bought the cheapest furnace they could, and installed it knowing that the next buyer would go "Oh! New furnace - won't have to worry about that for a long time." When I bought 3 years ago, I thought that having a furnace only 10 years old wasn't so bad, as they are supposed to last 20 years or more.
Sure they are, when they are sized correctly for the house! This furnace gave up and threw in the towel because not only was it cheap, it was undersized for the house. This lead to it working far too hard, far too long, and finally it gave up in disgust.
Now the hot water heater is starting to act up. I'm guessing that it too was installed at the same time, with the same point of view. Maximum profit from minimum investment. Works great for whoever made the money, but as the stooge who is the second person to own the house after that flip, I'm pissed off that someone else's parsimony is going to cost ME money to bring it up to an operating level that is worth more than an ant farting in the desert.