If you have income (int, div, soc sec), then those things are being reported to th IRS. Why not file a return to show the IRS there is no tax due instead of getting a notice years later when no one remembers what happened. Also, if you have a decedent final return and an estate return, if you file both you can reconcile the split of int and div between the two with what was reported on 1099's for the year.