Our couches are at least ten years old. TEN! They've survived a cat, a dog, a baby, three moves, countless juice spills and snack-dumping incidents, an endless parade of misdirected crayon use and frankly, they show every big of wear and tear they've earned. These things are nasty. NASTY. No matter how many times I scrubbed the arms, laundered the cushions, vacuumed the crevices, they still looked . . . disgusting. Comfortable, but disgusting.
After finally coming to the determination that it was time for a new set, I got pregnant again. Which means another small person to spit up, spill juice, dribble snacks, pour lotion on the arms, ETCETERA.
(This just in: children are foul, delightful little creatures.)
I didn't want to spend the money on a new set that would be destroyed in a matter of months, but I sure as hell didn't want to keep being positively MORTIFIED every time someone came into our home. Slipcovers seemed like an awful idea until a friend promised me that Sure-Fit would be different. (I sound like an infomercial. I swear, I bought these myself, and Sure-Fit doesn't even know who I am.)
I went with the Royal Diamond stretch, seen here, but in chocolate brown:

And BADOW! My couch doesn't look QUIIIITE as sleek as the photos would have you believe, and it's true, I have to do a fair amount of tucking and smoothing a few times throughout the day to make sure they don't look like bags, but overall, I am thrilled. THRILLED. My couches are no longer humiliating sacks of shame, the covers are completely (COMPLETELY!) machine washable, and I only spent $170 at Overstock for a couch AND a loveseat cover versus, say, thousands of dollars on a new set my kids are bound to demolish.
The covers are super-stretchy (well, the form-fit ones are anyway) and have a TON of elastic to fit around all the important bits on the couch. And they cover EVERYTHING, stem to stern, leaving only the tiny feet underneath, if you can even see those. Putting them on took about ten minutes, and I'll bet they'll be ready for their first wash next week. (I've heard they DO wash well, and since they're mostly synthetic---but soft, I swear---I'm not surprised.)
Do it! You won't be sorry. The only thing there is to be sorry about is buying red denim couches in 2001. Red denim shows EVERYTHING.