I'm one for deadlines. Sure, I'll pull my hair out and wonder how I'll ever meet all my deadlines, but then my mom (who keeps me sane) tells me that I'll get it done because I always do.
For me, the real problem is not having a deadline. If I don't know when I need to have a book drafted or revised by, I'm not as productive. And it's not by choice either. I find I'm just not as focused or as creative. I believe I've taught myself to be creative on command. It's a real thing. When I know I have to accomplish something, I'll do it. End of story. Tell me you'd like me to do something when I have time, and I'm lost. I need a deadline. This often means I create my own deadlines. And while I know I'm the one setting the deadline, I can still fool myself into believing it must be done. ;)
Are you like this? Do you need deadlines to motivate and push you toward your goals?