I rarely go above 4.3 volts for a 1.8ohm coil. Any higher and I immediately get burnt taste. But to each his own. If you like how it performs at a certain level then go balls out i say. Coils are relatively cheap and you can always boil them in water with some baking soda for 15 minutes. I find that gets rid of any and all taste on the coil and has everything clean again.