Several weeks ago, I picked up a special brush designed to clean the coils on a refrigerator.
I don’t know how big a difference this really makes — I’ve read articles saying it’s a miracle move that will increase your refrigerator’s efficiency by umpteen percent and/or keep it from burning your house down and killing you, and I’ve read articles saying it’s a total waste of time that won’t make any difference at all. The EPA says it’s a good idea, at least for older models, so I gave it a shot.
Couldn’t hurt. Might help. Either way, it was a good excuse to buy a pointy brush suitable for retrieving the wayward cat toys and dog biscuits that seem to find their way into otherwise unreachable locations.

The hardest part of the whole project was cleaning off the top of the fridge so I could pull it out from the wall without knocking anything off. (You probably don’t want to know what’s up there.)
I couldn’t remember whether the coils were on the back or the bottom of our refrigerator, so I started by running the brush underneath it just to be sure. No coils, but I extracted an impressive quantity of dust, dog hair, and cat kibbles. Bleah.
Once I’d cleaned underneath, I pulled the refrigerator out from the wall, got on a stepstool, and ran the brush down the back to clean both sides of the coils.

They weren’t terribly dirty, but cleaning them wasn’t terribly hard, either, so I’ll file this one under “probably worth the effort.” Our refrigerator is less than three years old, but if yours is an older model, I’d upgrade that assessment from “probably” to “definitely.” At worst, you’ll have a cleaner kitchen.
Emily