1. You're periods are irregular. - Birth control regulates the menstrual cycle which fixes the issue of irregularly. Simple, right?
2. You suffer from chronic acne. - Acne is usually caused by unbalanced hormones and can be mostly fixed when taking birth control regularly.
3. You want to prevent unwanted pregnancies. - This should be obvious, birth control is a pregnancy prevention method. I know, this is kind of a no-brainer.
4. You have a heavy menstrual flow. - Heavy menstrual flows are usually lightened and shorten when on birth control.
5. You suffer from severe menstrual cycle cramping. - Severe menstrual cycle cramping can be ridiculously painful but with the regulation of hormones and menstrual cycle the pain can be eased.