This is a difficult question to answer as each vaper is different. It is depended greatly on how much did you smoke and what strength of cigarettes were you using. A general rule of thumb is if you are a new vaper that has been smoking 20 cigarettes a day you should start around the 18mg/ml (1.8%). If you start into sub-ohm vaping or variable voltage or wattage you should start with lower strengths as this devices are more powerful. The best bet is to try a variety and see which suits you best.
