Desi, you are right in saying that it is all about confidence. My situation was just the opposite as yours when I purchased the old exams.
I had been out of school for almost 5 years when I decided to pursue dentistry. My gpa was low so I was planning to do a 1 year post-bacc, then take the DAT, and then apply. But, I had also started to volunteer at a dental clinic, and the dentist told me to go ahead and apply in the 2002 cylce since you just never know. So, during the month of Dec., I put together my application and submitted it online on the 30th. THen I spent the next month studying for the DAT. And if you have not been in a classroom for a long time, you forget even the basics. I did not know the difference between an aldehyde and an acid, or SN1 and SN2, heck I did not know what an SN1 reaction was!!!!! And the only thing I knew about gchem were the names of the elements! And theoretical biology was like mount everest....there was just soooo much.!
I literally lived at Kaplan during those weeks, but did not have the confidence since Kaplan exams are so tough. Would you believe when I took the first Kaplan exam, I scored about 6's across. Anyways, I purchased Stargirls exams, and practiced those in the 1 week preceding my DAT. I think those really helped me out for the gchem-ochem-bio-PAT, since that was valuable practice. Of course the questions are never the same as the actual DAT, but nevertheless your focus of relevant material changes. I took the DAT on Feb 1, 2002 and scored a 19 Aca/20pat/20reading.
Now after taking science classes for the past year, I feel I know so much of the material I should have known when I took the DAT. But some folks on SDN told me that my scores are OK despite my low gpa. So I am gonna wait and see; if I don't get any interview invites by October, then I will retake the DAT in November.
In essence. if you have enjoyed your science classes during the last two years and feel confident about your knowledge base, then the old exams are not really needed. But if you are in a situation like mine and rusty with your science knowledge, then I recommend these exams. They give you a better focus of the material you definitely should know. Just my 2 cents.