At least once a year, but more often can be even better. This replenishes your hair's lost moisture, making it look shinier are healthier.
Avoid washing your hair every day
Washing the hair everyday rids it of the natural oils which protect and keep it healthy. Shampoo hair only when it becomes oily.
It is important to eat healthy
Experts agree that poor diet causes hair to be dry and dull. Try to eat well-balanced meals composed of proteins, vitamins and minerals.
Use good conditioners
The best conditioners are not necessarily store-bought. You can use coconut, avocado or macadamia oil which are more effective since they penetrate deep into the scalp. Plus, you won't have to worry about side-effects because they are all natural.
Be sure to include plenty vitamin B12 in your diet
Beef has plenty of it.
Trim it a little bit regularly
Maybe it will not make them necessarily healthier, but they will look better as it can get rid of split ends.
Be nice to your hair
Don't comb it too hard. This causes friction which weakens your hair. If you really have to comb your often, just use a wide-toothed one.