Do I have to give an example for every question in part 3 of the speaking test?
No, you do not have to have an example for every single question in part 3 of the speaking test.
Examples are a means to extend answers. It's also possible to extend your answer by talking about a result of your answer and explanation, or even by briefly talking about the opposite of your initial response.
Most importantly, answer the question and explain your answer.
If an example comes to mind easily, use it, if not, don't worry, explain and extend your answer and let the examiner ask you a new question.
