How close you are to your ball depends on the situation. When a defender is right in front of you, you obviously don't want to take a big touch. However, if there is open space, you can take a bigger touch.
You will learn by experience how much you can get away with. Though taking a bigger touch allows your to move faster, it also may allow defenders to take the ball. Also, don't forget about goalies, many players take a big touch on breakaways, allowing the goalie to take the ball.