So, like most people, when I have KK pre I am trying to put as much money in the pot as possible via 3bets, 4bets, 5bet shoves.

At NL2 this was definitely the most profitable approach.

At NL5 I am not sure this is always the best approach and I think this is Villain dependent. An example of this is when I've 3bet with KK and face a 4bet.

- My default play is to 5bet because we can definitely get paid by JJ-QQ, AK and versus some Villains even lighter. The problem with this approach is that many Villains understand that 5bets are KK-AA most of the time and so will only continue with those hands. My thinking until now has always been to ignore the times we'll stack off KK vs AA preflop because the same will happen the other way around. I've only folded KK once and only because of very accurate stats on Villain over thousands of hands.

- Flat calling the 4bet also makes sense. I've experimented with this precisely versus those opponents that I feel won't call the 4bet with JJ-QQ. This seems to be very profitable when the flop comes low cards because they will stack off then. However, not so profitable if the flop is K or A high. Another benefit is if Villain had AA we may also get away from it if an A comes (not too likely but still happens).

What are your thoughts? Do you ever flat KK vs a 3bet / 4bet? If so, under what circumstances?

Standard 4bet is kk/AA. Its not hard to see why. If villian is shortstacking (intentionally) or a fish or a maniac then it can usually be like 55+ A9o+ as an example range. Maniac on the lower end, fish mostly broadways or higher pp. Unintentional shortstacking leads to desperation that can often be light 4-bet calls/shoves.

keep on track 3bet values, and cbet values.

if 3b is higher than 7 is likely he will 3bet light sometimes so insta 4bet, if you are 3betting and he 4bets, then check vpip to see how loose he play overall.

if he has cbet lower than 50 like < 45 then flat call his 3bet instead 4bet (in position) because is going to be more profitable outplay him postflop.

if is 200BB deep or more play it like any other hand because lower spr harder to get money with this hand and easier to get stacked with it.

to any other instance like vpip > 30 insta 4bet. to a higher 3bet like > 11 insta shove.

play it aggresive vs aggresive players and passive vs nits, regs.

in NL10 i've seen a lot of ppl who flat even AA into a 3bet also with KK, that sometimes is good (vs midstackers) because you want them to commit to any piece of the board due to a lower spr after the 3bet.