I've learned so much about writing over the past year and even since the beginning of 2011 after joining a couple of critique groups and attending two conferences. I've been trying to consider the comments made in the critiques and as a result I decided to take one suggestion (made by two different readers) and rewrite my ms to follow a slightly different plot line and see how it goes. I finished Part 1 (there are 3 parts) this weekend.
This happens to be WIP #1 for me (I have two others partially done). I hear a lot about how your first book is always a piece of trash and you should just write it and get it out of your system and move on. As a stupid newbie, I'm not sure I agree. Here's what I'm thinking.
1. I love the story. Even if it's never good enough to publish, I will get it formatted and have it printed so I have a copy of it. Because of this I want it to be the very best little story it can be.

2. This manuscript is the one I'm practicing on. It's completely finished, and the plot is solid (as others have confirmed for me). I look at this book kind of like I did when I taught myself how to read crochet instructions. My grandmother had taught me how to do a simple granny stitch, and I'd made several afghans over the years. But I didn't know how to read a pattern. I purchased a book, a thing of crochet string, and a hook of the correct size. I went to work and when I'd finish a certain technique, I'd unravel what I'd done and start on the next project. I did this until I could read just about any pattern. The string had been used to many times it had become discolored and I threw it away. But the experience was incredibly useful.
I'm on edit/rewrite 9 of my ms because I keep learning new techniques and writing pitfalls to watch out for. I don't feel like I'm wasting my time, and from the feedback I've received it's getting better (so hopefully I haven't taken the heart out of it by all my editing).
3. Once I'm finished with this one, I will (I hope) be better trained as I approach completing those other works.
I'm very much the personality type to start something and finish it. I love being able to say I completed a task--and this task I love. I hope I'm not like the old Harry/Hermione shippers--delusional--and hanging on when I should just set this project aside and let go.
What about you? Do you ever wonder if you've hung on too long? How do you decide it's okay to keep going or cut the apron strings?