Legal Question in Civil Litigation in California

Affirmative defenses are those that must be raised in the answer or can not then be brought up later. Other defenses can be raised later. But you wish to raise all defenses in yuor answer, such as the suit is barred because the debt was incurred more than 4 years ago, the amount of the debt is incorrect, partial payment was made, etc. If you are asking what defenses you should raise, without knowin gthe facts of your case none of us can answer such a general question.