The real value of a bug tracker is that you don't lose track of anything that needs to be fixed. This is probably more important if there is only one of you as if there are more because there is no one else to remind you of what you have forgotten. I can remeber a project in the past where we had a simple typo type bug and only one application developer (I was the db developer) and he didn't have time to do it the day the CEO brought it up and a couple of months later when the CEO noticed it was still there he went ballistic. When you are juggling a whole bunch of tasks and possible bugs, it is very easy to lose sight of something (especially something you think of as trivial). That incident resulted in us getting a bug tracker and putting all tasks not just bugs into it and it was one of the best things we ever did. Just being able to say to the client when he wants something new, "Well here is my current list of tasks. How important is it compared to these things?" makes it worth its weight in gold especially when you are the only person. It will help you develop time estimates to and give you a place to document discussions and decisions concerning the task so no one can come back later and say they didn't know you were going to do that.
