One of the microcoils I've made lasted for roughly 2 months. If I remember correctly, it was 10 wraps at 1.81 ohms with a 30g Kanthal. Changed the cotton wick once every week. I think it could have gone for another month but it was getting pretty dirty at the bottom and I could see some rust forming.
The funny part is that I forgot the amount of wraps, ohms, etc when I decided to wrap a new microcoil and it took some effort to remember it, which was the hardest part of it all.
I've made 2-3 microcoils after I discontinued the 2 month old microcoil and they were not successful. It was not due to the fact that I made them wrong but for some reason 10 wraps weren't cutting it for me. I was getting burnt cotton taste after 2 days and the flavor of the
juice was going mute. I don't know if it's due to the new silicone grommets on the Protank coil base but it didn't work out the same as my previous microcoil where I could get good performance for a week straight. And so, I decided to make a microcoil at 11 wraps, bringing the ohm to around 1.9-2.0 and it is working flawlessly.
Hopefully I won't forget how many wraps and ohm ratings on my next microcoil. If I do, I will just come back to this post heh.