In a poker game you are free to fold any hand at any time. You can fold as much as you want, there is no rule saying you can only fold X times. As long as you have chips to play with, you are allowed to fold.
You should fold preflop in a game of poker when you have weak starting cards that are unlikely to improve after the flop.
If you fold in poker and later realize you had a winning hand, you forfeit the opportunity to win the pot for that round.
I fold
You should fold poker hands when the odds of winning are low and the potential losses are high. This helps maximize your chances of winning in the long run.
You can fold a piece of paper without creasing it. When you fold the paper, the paper bends or curves, rather than forming a sharp crease.
That is called a "Walk"
If they didn't, they was gonna get rolled.
check/fold either way..
Constantly raise when he's in hands. Force him to make the choice of all-in/fold. Make him fold his blinds, etc.
When you fold in poker, you choose to not play your hand and give up any chance of winning the pot. This decision can impact the game by reducing the amount of money in the pot and potentially changing the dynamics of the remaining players' strategies.
This all depends on the "house rules" of the establishment you are playing at. Most casino's and cardrooms accept verbal announcements during the game. For instance if you say "raise", the dealer will expect you to raise. If you after that wish to check, you are not allowed to do so as you already announced a raise. A fold however can be dangerous when announcing verbally. If you fold you can say you fold and throw your cards away. Most poker rooms require that you throw your hand away rather then announcing the fold because this can lead to confusion at the table. The only way to verbally surrender your hand in poker is to say you fold.