depends how you play the game .... you have basically 3 states on it : attacking, counter-attacking and defending .... it's desirable you train hard to play attacking and counter attacking majority of the time, and only defending to counter attacking, not to "turtle" , to keep high defensive and passive stance, and ending letting the enemy/opponent take charge on the match .... and worse, putting you in the corner almost all rounds
fighting games work more or less like a game on turns : if you are fast, and attack first than your opponent, it's your turn; the next turn, is supposed to be from your opponent, and he/she has 2 options : counter attack or keep defending .... the smart player is the one that somehow uses his turn to attack, and the next turn (opponent action), he find a way to keep pressuring and attacking more, and ending kind using 2 turns for attack : the first one when he was faster, and the next, where his opponent made mistake not countering/reacting, and keep defending too much ...
as someone said, the deep knowledge of frame data, and what combo string to be used in the right moment, is a matter of importance in this game