I allways ask my fishing friends who keep logs what data they are recording. Is there some corrolation they can derive that isnt allready well known? The bennefit of keeping a log to remember date/fish for historical reference that might indicate seasonal patterns for area fished makes sense, but is there value otherwise? I go fishing anytime I can and dont bother with a log book because I figure any pattern that historical data has served to predict them is already known and well shared so why bother? Wouldnt it be better to rely on what those variables are and adjust current fishing accordingly? If the fish were not bitting I blame myself for wrong tactics and work to change and improve them or figure fish were not active at that time.