One easy way to prevent drains from clogging is to introduce very hot water into the drain pipes on a regular basis. Dishwaters are a great example of this. Because dishwashers expel hot water from their wash cycle at high volume, they clear out gunk such as congealed grease and food before it has a chance to accumulate in any great quantity.
You can do the same thing with sinks and bathtubs. Simply fill the basin with the hottest possible water every couple of weeks, let the drain out, and then follow with about thirty seconds of hot water from the tap. This helps "blow out" the slime and junk that builds up and causes drain clogs. While not the best thing for your energy savings, it is a tried-and-true method for preventing future drain clogs.