I've found that many of my friends still rely on their parents to handle their health things. This is such a problem. As an adult, you are responsible for your own health which includes scheduling doctor visits and the like. I cannot stress how important it is to schedule appointments for all facets of health annually or bi-annually. There are loads of doctor appointments you have to make so I'll break down some of the regular ones and hope that helps remind you to make the appointments if you haven't already!
Gynecologist - As soon as you enter your teenage years you should have been seeing one of these as a female. These doctors are female specialists, if you will. The job of this doctor is to keep your body functioning properly with regards to making sure there is no irregular stuff going on in between your legs or in your chest area to making sure your time of the month is regular and so forth. This doctor is to be seen once a year at minimum.
Optometrist - This is the eye doctor! If you're like me and don't need glasses, you forget to get your eyes checked regularly. I actually haven't had an appointment in two years but I'm fixing that next week as I have an appointment. I might need reading glasses as I'm on the computer a lot and sometimes get headaches but only time will tell. This is an annual doctor that you should be seeing.
Hygienist - This is the person in the dentist's office that handles your teeth cleaning! You're supposed to go once a year but if you have any issues like gum disease, you'll be required to go every six months or so. This is to make sure you don't have any cavities or any issues going on in your mouth.
Chiropractor - This is a doctor not many people even realize exists but I totally know you should go at least once a year. For me, my body is put through a lot as I do yoga and stuff so I try to get my body reset once a year. If you have any back pain or stiffness in the neck, this is the doctor you go to. Having said that, once a year you should go here and get your body reset. Our bones and whatnot move and need to be reset. It feels great but you need a good doctor or you can get serious pain.