For the cover maybe, but you can't wash down. You'd have to take that to a professional, which might be as expensive as just replacing it. Plus a good hour of ironing the cover if it was cotton.

Actually, you CAN wash down. I have done so multiple times and my family's duvets are just fine. Of course you shouldn't do it often, but accidents can happen, and then you kinda have to. Anyways: Use wool detergent (the lanolin re-fattens the down), and the cold hand wash program of your washing machine. DO NOT TUMBLE DRY! The down is vulnerable while wet and tumbling will break it, and ruin the duvet. Take out of the machine soaking wet. Lay flat on a dryer (either outside or in your bathroom - it will drip on your floor). When the surface of the upper side feels dry, turn it over and let it dry further. When the insides stop feeling clumpy, shake it up every couple of hours and put it down to dry again. Repeat until it is completely dry. It's ready to use again.

It takes about 30 seconds if you are doing it right.

With mine it has to be tied and pinned in or else it slides around in the cover, so it takes me about half an hour what with all the safety pins.

I use mostly cotton or flannel covers, so the duvets stay in place on their own (except for one of my sons, who manages to turn the duvet 90 degrees in the cover over some nights). Since it seems to be an ongoing thing for you, try this: sew slings of ribbon the size of a button hole on the inside of the corners of your covers (doesn't have to be pretty, nobody will see it). Sew buttons on the corners of your duvet. Done. Also: store the covers inside out in your closet. When you want to put the cover on, put your arms into the (still inside out) cover, with the corners in hand, grab the corners of your duvet (close the buttons first if you have them), then shake until the cover is right side out and over the duvet. (Close lower corner buttons if applicable.). Close cover. Done.

hardy har har good one lol