Could be lack of priming process, chain vaping, what coil HEAD (resistance) are you using and yes, are you using any known offender juices like NET and WTA and sweet or dark juice?
How much ELIQUID are you going through in 3 days, too, that is a FAR better representation of like, how much "use" you are getting. I had two Nautilus 2s (they use the same coil heads I think other than the nic salt one). Which, like has the least air and wick holes, so if you are using that coil, that is really going to gunk up the FASTEST.
I know there is a stern "use the nic salt coil for nic salts" so I'm not going to say OTHERWISE other than I used the 1.8 and 1.6 and even 0.7 coil with nic salts AT THE RIGHT PERCENTAGE. As long as it's not TOO HIGH and giving you nic sickness, you could certainly sub in your regular 1.8 coil and see if it lasts longer, and you MAY need to drop your nic salt percentage if you get nic overload symptoms.
BUT... you are basically using the most restricted and least vape producing coil that is going to die the fastest due to its construction. So, I'm not here to TELL you what to do or how to manage your intake but especially early on, chain vaping (even with waiting between hits) is going to cause shortened coil life, exacerbated by THAT COIL.
Unless you are using like 60 mg/ml nic salts and oh, vaping a few times every hour, I'm not SHOCKED by what you are describing, perhaps you can ask Aspire or other users about it but that coil is DESIGNED to be super restricted to limit how much vape you can "get" per puff. Etc.
I don't think I want to say too much more but yeah, talk to other users and knowing your nic salt percentage of nic would kinda be helpful etc.
Anna