With 10 ml per day, setting the mod at 17, resistance 0.6, in five to six heavy days it gives a burnt taste, so it needs changing. This applies to the orange box in the photo, which is now being replaced by the black orange one in the second photo, where the resistance lasted almost a month. I used to buy it for €20 for 5 coils and through Skroutz I found them for €12 per box. The bad thing is that there is no other brand for this specific atomizer, so that's why I gave it one star, because there is no zero!