depends on if im using TC or power, single or dual coils, and which juice. i get anywhere from 1 day to 2 weeks, and anywhere from 7ml to 30ml.
higher power dual coils with a dark/sweet juice might get a day and 7-10ml, TC single coil with a light/not so sweet juice, 2 weeks and 30ml.
sweeteners and dark colored juices will generally gunk up coils and caramelize in the wicks causing them to burn. higher wattage and low resistances will accelerate this process due to the higher heat outputs. finding a balance for you will take some time, i still LOVE my dark sweet custards on a .25 dual coil at 50 watts, but the wicks will last me about 1 fill of my squonker bottle before i get burnt flavor from the wicks.