Lakme - Eyeconic-Kajal has a ease in it.that means it is easy to use.easy to apply on eyes .and does not harm your eyes .as its a lakme product unless your eyes are very sensitive .but for the normal eyes you can use it every day .I use Lakme - Eye-conic - Kajal black every day in fact every time I go out its is very good and give a bold black look to my eyes.but as they say it is a smudge proof .long-lasting . 10 or 12 hours water proof Kajal . I personally don’t feel that nor I have experienced it .is goes lighter gradually after some time. or I can say within 1 or 2 hours.but as compared to other Kajals I think this is the best one and as I said I trust the lakme brand.