Hello Maka.. I am a relatively new vape-r so I cannot answer how long these last, but I have had one die in less than a week by putting an acidic
juice in it. Also, I have noticed that the dark/sweet fluids tend to clog up the coil with carbon after a
tank or two. Even with some of the more clear fluids I have found it good to clean it out after 2 or 3
tanks.
I have found that there is no consensus on how to clean these. The method I prefer is:
1. Carefully pry out the silicone seal and metal spout with a bent paperclip.
2. Put the clearomizer, silicone seal, metal spout, and tip into a small bowl.
3. Fill the bowl with the cheapest vodka you can find to cover the parts.
4. Let soak several hours then 'swish' the parts around in the vodka till clean.
5. Put parts aside in a safe, dry location until dried out or use blowdryer on low.
6. Reassemble the parts and refill clearomizer then turn tank thoroughly to prime wick.
7. If wick was still 'wet' with the alcohol it may take a few vapes to break in.
I am sure there are many other opinions out there, and there are several videos on YouTube that also show how to remove the silicon seal and metal spout if you cannot figure this part out from my description.
~Cheers!