Yes. When you menstruate, you will lose on average about 2 Tablespoons of blood, but some girls can lose even more than this. A fully soaked normal size pad or tampon holds only a teaspoon of liquid, so if you don’t change your pad, you may leak or spill over. Also, it is uncomfortable to wear a soaked pad. You will want to change your pad every few hours. This is also for sanitary reasons.