Have you seen this month’s Twist Collective?
There are two good articles in it:
Darn It All, showing four different methods of darning knits, and The Error of Our Ways Part 3, which gives different methods to shorten or lengthen sleeves (or the body) of a sweater.
CabledSheep 
I’m ready to try my hand at darning socks now!
How is the floppy paw?
This is the best Twist in a couple of years! Love the articles and half the designs, too!
I saw the article on the sleeves but missed the darning. Need to check that out. I think I have at least 3 pairs of socks to mend. o.0
I’ve been searching for a really good tutorial for the Reknit & Graft method to rescue a favorite hat I knit for my son; this is perfect! Now all I need to do is get up enough courage & patience to just do it. Thanks for the link!
The darning article makes me understand I probably will wear mismatched singles before I get to darning.
LOL @ Laurie’s comment. I keep thinking I’ll darn things…particularly given how fast they wear out and how slow I knit them, but…