Generally I subscribe to the Yarn Harlot's "oh darn" method of sock repair, whereby one holds worn through, thin, hole ridden socks over a waste receptacle, says "oh darn" in a clear voice, and drops the socks in the waste bin. I figure I have lots of sock yarn in the stash and I like knitting socks, and sometimes the holes are just too big to deal with any other way.
Not my Monkey socks. I like them a lot. They fit right and the yarn (Oak Grove) is pretty. I properly darned the toes on these a few times, switched the foot I wore them on to wear out another spot and I even babied them a bit.
This winter when I went to wear them, I noticed another hole in the toe and that there really wasn't much left to darn. I decided to rip out the toe and add a brand new one.
This is relatively easy on a cuff-down sock.
First, snip the yarn below the lowest hole. Grab a dpn and start unravelling the yarn.
I found I sometimes had to unravel a couple of rows because some of the darning yarn was in the lower rows. When I was done I had a little toe cup full of holes off the sock.
Then all you have to do is put the live stitches back on the needles and work a new toe. I used Kate Atherley's method so I don't even have to graft. And, I found a teeny little bit of the original yarn so my toes match.