Very few people have a habit of delivering early. Most people wait until the last minute to start on a project and then deliver right before (or more often right after) the deadline. I've found this to be especially true with graphic designers and web developers, but I think most of us are guilty of this at some point.
Here's a really good approach to deadlines I learned from Seth Godin during SAMBA.
Don't use other people's deadlines and never do anything at the last minute.
If someone gives you a deadline, don't use it. Instead set your own deadline ahead of theirs. Get in the habit of shipping early. You'll exceed the other person's expectations.
How do you treat deadlines?