There are few things more aggravating than finishing a sweater and discovering the sleeves are an inch, or 2, or 3, too long. All that knitting, all that seaming. Though still not fun, I recently figured out how to shorten the sleeves without taking everything apart.
Snip a stitch or two at the cuff. Good project for when you’re watching TV. Unravel back to the length you need. Then, using some of that raveled yarn, take a crochet hook of the appropriate size and crochet a new border around the sleeve bottom. I use single crochet, but you can do picots or whatever you please. No, the cuff isn’t ribbed, but it’s still pretty and now you can wear a sweater that fits properly. Ta daaa!