@rcooley25 , it isn't often that it happens.  Dascpa mentions one instance.  Another potential is with higher income folks with similar incomes.  Unusual tax laws sometimes come to call like in the cases of the unemployment exclusion a couple of years back and once in a while with the health insurance premium credit.  Probably in those 54 years you maybe missed out on one or two returns where you could have saved your clients two dollars so I wouldn't lose a lot of sleep over it.