We just built a new home, and I'm wondering what routine things need to be done to keep everything working, well maintained, and happy. I can think of a lot of things, but the problem with any question like this is you never know what you don't know. So... I'm thinking a community wiki would be a helpful resource for everyone, and a good way to find things I may have missed.
To that end, I'm not going to explain features that went into our home. Our home may not have features which other people would need to ask about, and I may forget a feature which needs maintenance anyway. Please try to keep answers in roughly the form of "Home Feature, Maintenance Required, Frequency." Then a brief description of what might be helpful to know about performing that maintenance. I'd like to encourage links to other questions, and if a particular piece of maintenance needs deep discussion, creating a new question and linking to it.