Double Deck: New Cards

I play in the Midwest. Can anyone please tell me how often, roughly, new cards are brought in for a 'typical' double deck game in the Midwest or wherever you play?

No, I try to make decisions in the casino that are 'above board.' In fact, I have seriously questioned whether it's even dishonest for me to rathole chips. I know, it sounds silly. I believe :) I have recently made a decision that it is fine for me to rathole chips but not fine for me to not tell the dealer when she/he makes a mistake either in my favor or not in my favor, and whether anybody but me notices the mistake or not.

By the way, this is one issue about which I disagree with Ian Andersen. For example, I am not sure dealers may not experience some kind of negative consequence if they make a player-friendly mistake (especially for high stakes) which is not addressed in 'real time.' Recently a female dealer paid me for a loss or a push (I can't remember which). She seemed embarrassed, which is understandable, and she thanked me afterward for pointing it out. After all, I would want to be treated as such if I were a dealer (and you know they all make mistakes at some point).

By the way, have any of you noticed that those dealers who seem very (too?) quick (to the point of gesturing to grab the cards up even if you did not bust) to scoop up your cards immediately after placing your bust card on the felt tend to be the dealers who are more inclined to make errors of the casino-friendly type as opposed to player-friendly errors? Finally, it seems to me that perhaps female dealers are more likely to make player-friendly errors while male dealers are more likely to make casino-friendly errors. Just something to consider, maybe now or on your next casino trip...