External factors are more influenced by the way you treat your hair. For the sake of appearance, people usually give an over-treatment to their hair such as changing color frequently, using an overheated blow-dryer, curling iron, flat iron, using strong tension and certain products containing harsh chemical agents, using improper product for the hair texture and condition, using highly dense combs, etc. Wearing hats and helms continuously also causes too much humidity to hair and finally damages them. To avoid these problems above, you should recognize your main hair specifics and give them proper care. Always select products that are suitable for your hair type, the more natural the product is, the lower the risk will be. Use some tools only when necessary. To minimize breakage, make sure that your hair is thoroughly wet before applying shampoo, use very little of shampoo and rub it between your palms first, lather for no more than 30 seconds. After shampooing, rinse your hair with cooler water to seal moisture in the hair shafts. To distribute the natural oils in your hair, bend over and brush your scalp and hair from back to front until the scalp tingles; then massage the scalp with your fingertips. Towel-dry your hair thoroughly before using a blow dryer. You’ll save time and avoid damaging your hair with too much heat. If you have got short hair it is unnecessary to use a blow dryer at all, simply towel-dry an excess moisture and let your hair dry naturally. The best hair combing after wash - even without any hair brushes - just by means of your fingers. But if this is unacceptable, then wet hair must be combed through with a fewer teeth comb starting from the tips and gradually "climbing up" to the roots, each time combing through entire hair length. To cut down on static electricity, dampen your hairbrush before brushing dry hair. Always avoid using brushes on wet hair as it is a subject to breakage, only combs allowed. Comb out bends and knots, also use a  minimal number of modeling tools and products that should not overwhelm the hair making them sticky and dirty, so you basically have to re-wash them again. And it is always wise to use special products to protect hair from the heat and other environmental factors that are mostly caused by sun rays, air pollution, water contaminated water. etc., also avoid tight constrict hair gums and similar accessories. We all know that one of the hair functions is to protect our heads from sunburning, but it does not mean that you may have your head sun-bathing continuously as the heat can damage your hair. If you wish to keep your hair healthy and strong, you should not forget about their preventive strengthening including scalp massages and balanced nurtition.