I don't audit, current or past years or prior preparer. But, I have to read the prior returns of a new client to see if they have a capital loss, NOL, how many times they took the AOC, who the partners/shareholders/beneficiaries are on 1065s/1120Ss/1041s, whether the person sitting at my desk has been the tax matters partner/executor, compare year-to-year to give me clues what might be missing, get the EIN of the childcare provider, are paying back that homeowner's credit, did they already use up the lifetime energy credit, get depreciation schedules, what was their state refund/did they itemize/compute how much is taxable so looking at prior year AMT, and on and on. I'm not looking for mistakes. I'm looking for information to prepare the most complete and accurate returns for my client this year.