Each juice is going to taste differently at different wattages and in different tanks. (IMO) rinse and dry your coil (if you so desire) and refill, priming the coil again and moving slooowllly up in wattage, until you hit a sweet spot. With that said, some juices just taste gnarly to me at any wattage, on any coil. You'll soon discover preferences. One of my favorite storebought juices was coco and they colored it so that it was tarry dark. I can really only run a tank or two of that juice in drop-in coil tanks, before they die. It doesn't matter if it's day one or 12, so I save that stuff for when my coil is about to die. With that said, now that I DIY I have some clear chocolate flavors, that I hope I will find enjoyable, and have really moved away from storebought, period. They all taste too strong and harsh to me now that my tastebuds have grown back.
AND I FINALLY GAINED FIVE POUNDS!!!! Yay. I knew all that eating and inactivity would help me out, LOL. E-juice has no calories, unfortunately, but only 10 more lbs to go, YAY!!!! (I got pretty pneumonia chic at the end of my smoking and it wasn't good at all). Of course, the husband briefly thought I might be pregnant (thanks there, buddy!) but no, my vastly improved eating habits all have to do with how things taste, LOL.
But yes, Stav, darker and sweeter juices are known coil killers. You may want to go someplace that has an e-juice tasting bar to see some profiles you like of juices that aren't too thick or sweet, if such a thing exists near you, to save you from flavors you hate.. Otherwise, some online vendors sell tasting samples in small bottles to give a sense of what they have to offer. Best of luck,
Anna