Why your coils die in four days (and how to get three weeks)

A mesh coil should last ten days to three weeks. If yours is dying in four, something specific is happening, and it is almost certainly one of the three things below.

Sweetener is the main culprit

Sucralose does not vapourise cleanly. It caramelises onto the coil, building a dark crust that insulates the wire from the cotton and progressively kills flavour. Heavily sweetened dessert and candy liquids will gum a mesh coil in three to five days no matter what else you do right.

This is not a defect in the liquid or the coil — it is chemistry. If you want a fortnight out of your coils, the single most effective change is moving to a less sweetened flavour. Unsweetened fruit and menthol liquids generally last considerably longer in the same hardware.

Priming, again

Firing a coil before the cotton is saturated scorches it immediately, and a scorched coil never recovers. Five drops per wicking port, fill, wait five minutes. Then start twenty per cent below the rated wattage for the first tank and work up.

Running above the rated wattage

The wattage range printed on a coil is not a suggestion. Running a 0.2Ω mesh rated at 45–65W up at 80W will produce more vapour and shorten its life by more than half, because the cotton cannot wick fast enough to keep up with the evaporation rate. The result is a partial dry burn on every draw.

Things that do not matter as much as people think

• Coil brand, provided it is authentic. Counterfeits are a real problem; genuine coils from different manufacturers perform broadly similarly.
• VG/PG ratio, within reason. Very high VG in a tight MTL coil will struggle, but 70/30 is fine in almost everything.
• Letting a tank run low. It is not ideal, but it is a smaller factor than sweetener by a wide margin.
• Coloured liquids. Dark liquid is usually oxidised vanillin, which is harmless and unrelated to coil life.