I usually leave out tail number, I'm just not that obsessive. Family vacations were tough for me to remember too. I can usually get month and year by tracking down old pictures (mom always wrote mo/yr on the back). My dad flew a ton for business on TWA and US Air, and every summer we'd fly somewhere off his miles, so I just list one of those. I've been able to recapture data from the last few years by looking at my past trips on Orbitz, and by skimming my frequent flyer accounts.