Noob question: should you always pot preflop when you play the button?

[RoundTower]

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imagine you are playing blackjack and the count is well in your favor. do you bet 3x your normal amount so that you don't "over-commit" before seeing your cards? or do you bet the maximum?

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I never really understood this in blackjack, aren't there some cases where you're "meant to" bet in between the minimum and the maximum? Other than to decrease ror or avoid being caught I don't see why, but I understand it's true.