A filing-status checklist can help identify which years need attention during a back tax review. You can ask for help before completing that checklist yourself.
Use evidence-based status labels
Create columns that describe what you actually hold: return copy found, filing confirmation located, account correspondence available, and follow-up question recorded. Leave a field open when its source is missing. A copy saved on a computer may describe the prepared return without establishing every later processing event. Write the date and source of any status information you use so another reader can understand why the entry was marked. Avoid replacing several uncertain fields with one confident completion check.
Review each gap as a separate task
A missing copy and unclear filing history need different follow-up work. Identify which gap prevents you from understanding the year, then ask where the relevant evidence could be obtained or checked. Keep your notes short enough to compare periods, with fuller explanations in the individual folders. At the end of the checklist, list questions that concern more than one year rather than repeating an assumed answer in every row. Bring the checklist to a discussion as a working inventory, not a conclusion about the account.