Do you practice at most two parts at a time? I always do it twice, and I always think it's better to practice more once, otherwise some parts can only be practiced once a week.
What kind of fitness exercise are you not allowed to take part in? As you feel, it is better to practice more parts. Fitness is not bodybuilding. You must practice a certain muscle. You must do all-round exercise to be strong. You should do what you feel, so it's right.