I have in my Simple Family Tree program a place for notes on each person, and I indicate where there is date confusion, difference in spelling of names, doubt as to which wife in 1732 my supposed ancestor actually married...etc. I always try to find several corroborating bits of data that are not simply copy & paste duplicates. All of mine except for one the upper twigs of one branch are pretty well double-checked. It helps when there are not 3 or 4 John J. Jones in successive generations.