With all the advice, number of books out there, forums like this, and TV poker. Most players know that AA, KK are the only real all in preflop hands in normal situations. Is this not one of the ways the game has moved on?

Personally, I've lost $400 with KK vs AA, and over 50-60k hands of 25NL it's my biggest leak, So my advice is very subjective. (KK is a lifetime loser by $100!).

Nowadays I want a read that they felt <KK pf or they are wildly aggressive before I shove over 4bets or call pushes pf with KK. Put it this way. If they turned their hand over and showed you AA, you'd fold. So AI is a mistake if they have AA. It is also the biggest mistake you can make (because you can't get any more in behind). Since 4 betting with < KK is not the norm anymore, why should we advocate always going all the way?

Disclaimer: My being stung by KK is a very personal thing and has obviously affected the way I view playing it.