It's also a good idea to pour a bit of something like green goblin down the drains once a month or so. I find it helps to prevent the otherwise inevitable buildup from soap scum and whatever fats n junk that make it down there.

Also, always wipe greasy kitchen stuff with a napkin or paper towel and toss it in the trash. Soap pans n things to make sure fatty water isn't going down. Cleaning out the kitchen pipes after year's of neglect sucks!