Check out this post from Golf Digest-Tracking Golf Shot Data is Big
Tracking each shot in a notebook can help anyone play better. Many golfers believe this approach is cumbersome and takes the feel out of the game. Also, why do I need to know what I did on certain hole 15 years ago? The answer is that you use the data of each shot for the current round and correctly chose the correct club for the conditions. If you hit an 8 iron 145 yards from the fairway into the wind on hole 1 and track it, then you can use that data later in the round when you face a similar situation. Conditions of the turf, air, wind, and temperature can have a great influence on how far you are currently carrying each club. Having live data for the current day will lower your scores. Using and yardage book or scorecard notebook is a smart move if you truly want to shoot lower scores.