When you reach the turn in fixed-limit games, betting limits double, and you should only play the turn in those games if you have a good hand, a draw that figures to win a big pot if you catch the card you need on the river, or have reason to believe that a bet will cause your opponent to fold.
In no-limit hold’em, things can get dicey. If you’ve made it to the turn the pot may well have grown large enough so that any bet threatens to put your entire stack at risk. If you’ve reached the turn in a no-limit game you will probably have a hand you think is in the lead and so you’ve been the one who’s doing the betting, or you have a draw and have managed to get this far at a small enough cost to justify chasing the card needed to promote your hand from one with potential to the best hand.
