I tried it last year - to complete on old novel that's been gathering dust for a few years now. It's the final book in my military scifi trilogy and I've simply been sitting on it too long. NaNoWriMo 2016 seemed like a great opportunity to punch out 50,000 more words and perhaps finish it. After a great initial few days I made one of the silliest mistakes a writer can make when trying to finish this challenge...I got a puppy.
Her name was Hestia and she was a ten week old shepard/husky cross that demanded constant attention (housebreaking was a massive challenge) and she ultimately sank my aspirations to finish. I wasn't too hard on myself, mind, as I did add another 36,000 words to the book - no small feat in the end, but I never finished it. I didn't touch it again since I was focusing on a hard edit of my third Scarlet Bastards book, The Bone Witch (my 2014 NaNoWriMo success story).
So here I am into day four of NaNoWriMo 2017 with the same plan in place - finish Titan Rising. I'm a day behind already though I'm hoping to play catch up this weekend, but I feel if I can finish this book, and in the end, this series, I'll be pretty happy and ready to move on to some new projects.
Wish me luck!