I don't take care of my ends besides regular dusting, but most people who do, seal them with something like an oil. One of my idols, Msa, just used to seal her hair with Castor oil. After washing/conditioning, she'd rinse and then seal it while wet with Castor oil.
Baggying (wearing a plastic cap) at night helps to keep moisture on your hair instead of on your scarf or pillow. Once you get to shoulder length, then sealing and protective styling will be your answer.
The ends of your hair are the oldest part of your hair and the open end of your hair so moisture is easily lost, so regular dusting does keep splits to a minimum and does prevent the hair from thinning over time. If you then start protective styling in addition to sealing once your hair is long enough (meaning your ends are hidden from the drying air), then you may find you don't need to dust as often and your ends remain full and healthy.