Waste of time! Good players vary their play. Just because they stole alot of blinds yesterday doesn't mean they are not playing squeeky tight today.
The only notes I make are on people who complain about slow play, so that if I get in a game with them again, I can play slow and try to get them on tilt.
LOL! Everyone's entitled to their opinion, even if it's wrong!!
You're right that good players
DO vary their play, but out of all the players all the different levels of play, what percentage of them do you think should be considered "good players?" As is brought up here VERY often, there are a TON of fish and donks out there, who are
not good players and
WILL make the same mistakes over and over and over again, so what's it hurt to take notes on them?
And yes, players can improve over time, so that's where dating your notes comes into play. And another thing, I don't think that anyone that's recommending taking notes would ever advise making decisions solely based upon what those notes might tell you about a player, but rather that they are just another little piece of info that can be added to all the others available to you when you are making a poker decision. There's nothing that's a "waste of time" about having as much info to consider as possible when you are thinking about your next move.