On your question... it's a much bigger error to fold a pot where you have proper equity, then to call one where you are a bit short of proper odds.

Say you have 10% equity and are getting only 8-1 to call. calling with bad odds here costs you .1 of a bet (spending .9 bets to protect .8 bets equity). Now say you're getting 9-1 to call... folding costs you .9 bets, which is 9 times as big a mistake.

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-You may not know this, but poker is a game of incomplete information.