How often I need to wash hairs?

This is depends from your mode of life,work, style,and for true this is very bad if you hairs will mud,as with dandruff for other, but its depends from you always, at work if having a shower,wash everyday, if you apply laquer, wash hairs on evening time with ph neutral shampoo near, but do not wash hairs often with shampoo against dandruff, they will have just wash off dandruff, not a reason fighting, but peeling shampoos use everyday,as cure, by instruction chacking, use by an own type of hair, or for all type of hairs, he is neutral by effect an own.  After swimming in the sea,always wash hairs, salt,and sun damage hairs,they will dry, bleakness,select a good shampoo.
Wash a healthy hairs just one time/week  is good, but if you do not use lacquers,gels,foams, curly,as selecting a soft shampoo, if to zealous,skin of head will dry , but in shower wear hat for shower,ahe care hairs for water entering ,as for normal hairs they are healthy use a shampoo for normal hairs or for all hairs types, not simple care are for greasy, dry ,combined hairs needing.
An often dryness, sun, comb will damage hairs, they will be a dry, brakeless,they are not save, wash theirs till one time for 10 days, as with shampoo of fatty substances,as moisturzing polymeres, as oil of sprouts millet, jojoba, soya, avocado, lanolin, egg lecithin, as in washing hairs will be elastic and tight, as therefore dry hairs will be a care right, nourishing, restoring and of  humidity.
Greasy hairs do not often wash,as in often washing an acid mantle  will bad, oily glands will compensate a fat enough,and produce will intensively,as for everyday washing use a soft shampoo for oily hairs with cleaning oil,and less foaming his, is very softer. A good if will add an herbs as tannins of,are rosemary, caraway, horsetail, which regulate a work for oily glands and giving for hairs top a light  roughness ,as raising a hairs rubbing on each other and hairstyle keeping longer,than in greasy hairs.Anew shampoo of South America extract Panama soap tree as best effect for greasy hairs,like in wetting paper, and fat will absorb, does not stimulate an oily glands. And oily hairs will less if to wash in  bark oak,as  without a soap, of three tbl.sp. bark  oak ads in one l. of hot water,cook 15 minutes on weak fire,cool,filter, wash hairs for one time at three days within two months. After washing rinse of chamomile in light hairs as with buds Humulus two tbl.sp. for one l. of water or petals of a sunflower as two tbl.sp. boiling in one l. of water for 5 minutes, dark hairs of horse tail, bark oak, nettle as two tbl.sp. every for one l. of water .If hairs are fast  oiliness as from wash till wash rub of herbs infusion Biden, sage, chamomile, as three tbl.sp. for 0.5 l. of hot water, of horse tail,and flowers arnica as two tbl.sp.  mass for two glasses of hot water .Do not use rinses for thin hairs,,use special shampoos.