Most people want help from a tax professional so that they can minimize their taxes. They often come in to see a tax professional at the last minute with their disorganized array of information. Those are the types of potential clients that I attempt to screen out for several reasons. They are:
1) Attempting to minimize their taxes (or upset with owing taxes) after the fact. There isn't much you can do after the fact.
2) Unable to claim all of their potential deductions because they have not kept track of them during the year.
This brings me back to the title of this post. Garbage in = garbage out. It applies to almost everything in life, including taxes. Not even the best tax accountant or CPA can help you if you don't have some way to track your expenses or deductions. If you have been weak in this aspect of your life then reconsider its importance because it has the potential to save you a good deal of money in the long run.