I don't quite do it as simply as Liz advocates. Sometimes I wish I had. I list the censuses by year for another program so do the same here, i.e., VT 1900. Everything else starts with a 2 letter designate for each of the four grandparent lines, and then straight numbering. Sometimes I add two letters to the end of the census number when several lines converge, but not routinely. And, it makes no difference to me if a birth and and obit are side by side, as long as I can find them when I want them. I would like an index so I could find things easier when the computer malfunctions! Otherwise, I think you will find the simpler you make it the easier it will be on all counts. Jane