I'm glad to see that others also keep a flight log. I thought I was being overly compulsive about doing so, but naturally started keeping one because 1) as an engineer I find it useful to go back to notes to see what did or didn't work and 2) as a full scale airplane pilot it is standard practice. Other than standard data fields, such as date,place, wind, model, etc., I find it useful to include who was with me. It helps me track the progress of my "students".