The Nautilus tanks offer believe 1.5 and 1.8ohm coil heads, the Protank2/3/Aerotank can range from 1.5 to 1.8 all 3, and up to 2.5ohm on the Protank 2.
Coil head longevity is affected by how high in wattage you are pushing them (higher the quicker they can burn out), thickness of the liquid (30pg/70vg max thickest to 70pg/30vg thinnest is generally the ball park for them, median about a 50/50 blend) but thicker liquids take longer to wick and the VG carmelizes quicker the more there is, sweetness of the liquid also affects wicks clogging sweeter the quicker the sweeteners carmelize and clog wicking, darkness of the liquid is also another clog hog, darker the liquid the quicker it gunks up wicks, and yes if you are sucking continually on a mod like a pacifier will decrease coil head life