[Schneids]

One last thing about this hand that might be obvious to some but is still point-worthy:

If you had 5h4h instead of 44, you would absolutely almost never checkraise this flop after a bet and a call.

The difference is pretty easy to notice: With 54, if you're behind CO, you likely have 5 outs instead of 2. So, say with 54, if you get 3-bet on the flop, or raised on the turn, you are basically going to have to see a river because of the pot size and the fact you have a likely 5 outer. With 44, you can fold to further aggression because your 2 outer isn't giving you odds to draw. Basically, checkraising with 54 would be setting yourself up for making a compounding error (one in which at each particular juncture, the play/odds are fine, however, adding up the total invested compared to your overall odds, it's a mistake).

After reading this, you might then say why checkraise 44 at all? Or even, why not checkraise this situation almost 100% of the time no matter what you have? Because 44 has showdown value and beats the high card bluff-catching call downs you might get (so it's for value, vs the field's range), and 44 is easy to dump if you receive further aggression (due to lack of outs).