If you are developing code, even on a team of one, without an organized database listing all known bugs in the code, you are simply going to ship low quality code. On good software teams, not only is the bug database used universally, but people get into the habit of using the bug database to make their own "to-do" lists, they set their default page in their web browser to the list of bugs assigned to them, and they start wishing that they could assign bugs to the office manager to stock more Mountain Dew.
More in Painless Bug Tracking article by Joel Spolsky