I have been using my TFV4 for almost a year now with a Sigelei 150W TC mod, usually running wattage between 70-73. I use the TF-S6 sextuple coils because they don't spit and pop like the TF-Q4 coils. My questions is this: Is there a different life expectancy on a coil that stays in the sealed package until ready to use versus one that has been out of the package for an undetermined amount of time? I have noticed that the five pack of coils I purchase online that I keep in the sealed package until ready to swap out tend to last me between 1.5 and 2 weeks, whereas the ones I buy that are open to "fresh air" from my local vape shop tend to last up to a week max. I use the same brand 80/20 juice with each type, so I don't think it's a juice issue. I've tried searching the forum to see if anyone else has this issue, but am coming up with nothing.