Can dry heels heal by themselves or do you need medical assistance?

Yes: Avoid wearing backless sandals or slippers. Use a pummus stone to smooth down the dryness after showering. Apply vaseline to the heels and cover with white cotton sock before going to bed.

Yes, but: Skin is mostly water, as it dries out the thickened skin on the heel begins to shrink. This causes increased tension on the skin and cracking occurs. Using a cream two times a day can help. Some people need a stronger cream. Using a cream with urea (40% works well) is what i recommend (this is a prescription). No matter how you clear up the problem, you need to be diligent. It will return.

Moisturize them: Don't wait for them to start cracking open. If they do they will be painful and can be a portal of entry for bacteria or fungus. Try applying something like a thin layer of vaseline or other mositurizer. If this fails then see your podiatrist or dermatologist.