I also use worksheets I've devised over the years to give me check figures for Federal AGI, Itemized deductions, Federal taxable Income and the same for state.  I know what you mean about their evolution over the last three seasons!  But they are the reason I was able to find this glitch last month.  And despite the time they add to the preparer's time, they significantly reduce my checking time. Not to mention the mistakes they catch.