raise the flop or wait for the turn headsup?

Here's the situation:

6 player max game, .50/1 on Party. I'm on button with KK, I raise, one caller. Flop comes:

5 8 Q, rainbow

I get bet into, I put him on AQ, do I raise now? Or wait for the turn to raise? This seems obvious to me, I should wait for the turn. On average I'll lose an extra 1/2 bet if he catches (reraise on the turn costs me 1, no raise on flop saves me 1/2) and I'll win an extra 1/2 bet if I win. Since my hand will usually holdup I want to wait to raise?

Am I missing something?

How about, same situation, but two hearts on the flop. Do I raise the flop now? I'm still saying no, more times than not I'm going to win and want that extra 1/2 bet.

How about 3 hearts on the flop? This is where it gets tricky. Do I still wait for the turn to raise knowing a scare card is 11/47 chance of hitting preventing me from raising the turn?

How about a scarier looking flop, like K Q J when I'm holding AA.

I've laid out a few situations here, when should you raise on the flop and when should you wait to raise on the turn when in last position headsup?

[wackjob]

HU I might pop him on the turn, and sometimes I might wait till the river if the board is really bare of scary draw type stuff.

[TheMetetron]

I play a crapload of stuff fast here so I raise.