Is it advisable to use kez sjampoe daily to wash my hair , or only when affected ?

Usually not daily: It depends on what is being treated, and how things are going. For treating dandruff, one source suggests: Use twice weekly (every 3 or 4 days) for 2 to 4 weeks. Then, for prophylaxis of (preventing) dandruff: Use once a week. Regular shampoo can be used on other occasions of hair-washing. One's doctor can recheck the scalp if problems persist.