If you are building standard kenthal coils for an RDA, you should be able to withstand many uses from a set of coils (or just one). Personally, my coils last for several months, and retain zero unwanted flavors with proper care. I change cotton every three days due to sticking with one flavor. During each cotton change, be sure to burn-off your coils at a LOW WATTAGE. This will prevent your coils from hotspotting near the post, therefore shorting your unit. Use a coil brush, in addition to burning off unwanted juice/gunk. Also, unnecessarily adjusting your coils on the post will shorten its life because you are losing integrity of the metal by bending/flexing, etc. Sent from my LGLS775 using Tapatalk