Our scalp skin type directly influences the type of our hair. It's like as scalp skin state determines the hair state, because the skin is the source of hair health and beauty. To have a healthy and beautiful hair you must have a healthy scalp skin, because the skin supplies the hair all necessary nutrients and strength to develop, grow and renew their cycle. The hair is divided in general into three main types: normal, oily and dry. It is also true that lately we are increasingly faced with the mixed and damaged hair types.
Normal hair - a normal healthy skin, which lacks any anomalies or problems in most cases leads to normal hair. Hairs are considered to be normal if they are not getting greasy 3 to 4 days and at the same time do not lose their natural sheen and flexibility. Normal, healthy hair are elastic, easy to form hair styles, they are easy to comb through dry or wet - because they have a solid, soft and shiny shaft with a smooth and seamless keratinized layer and almost no split ends. 
Greasy hair - oily skin leads directly to this hair type. Such hair look disorderly, sticky like moist, hairstyle quickly loses friability. When the fatty glands produce more fat than necessary, there is a need to wash hair every day or even more frequently. As a rule, the increase in head skin fatty gland secretion is followed by increased secretion of facial fatty glands and scalp sweating.
Dry hair - when the fatty gland secretion is insufficient, the scalp and hair becomes dry, very sensitive and dehydrated (loss of natural moisture). Also lately dry hair may be a result of a range of natural external factors and chemical processes. Dry hairs are britle, inelastic, lack luster; they have very hard keratin fibers and split ends. It is difficult to create a desired hair style out of dry hair, they often may start to grow poorly and break at the roots.
Mixed hair - oily scalp and dry hair is a combination of the lately relatively common phenomenon. Such cases should be handled with your hair care respectively.

Damaged hair - different external effects on the hair, such as natural (environment - wear), mechanical (brushing, tangling, etc.) and chemical (hair coloring, perming, etc.) cause relevantly natural, mechanical and chemical damages.

Hair type is always important to know on order to choose the proper hair and skin care. Also choice of proper care is affected besides your hair type by your hair sort. It is also important to remember that over time the hair type can change, just as may change and skin type.