I thought i would post this in this section as it is more pertinant to newbies. When we convert to ecigs, we always try to work out how many cartridges we should use, how much the equate to in normal cigs and what level of nicotine cartdriges to go for. Let me put my reasoning after my 1st few weeks and days. The sellers advertise that there cartridges are the equivalent to 20 cigs or a packet. This true and untrue depending on your take on it. Untrue if you consider the amount of puffs you would take during a packet of cigarettes. Most people would say a typical cartridge from say a 901 style ecig will last between 6 and 10 cigs depending on how you smoke. True is the mg of nickotine a cartridge will supply compared to a packet of cigs. A typical packet of 20 will contain about 22mg of nicotine. A typical high nicotine cartridge will contain about 18mg. Almost a full packet. How should I set my level and avoid too much nicotine If you were like me, I smoked 20 - 30 cigs a day, equivalent to around 35mg of Nicotine per day. However moving to ecigs, I used them as a direct replacement for the old method and found I puffed on it at least 20 - 30 times a day for 5 - 6 puffs at a time. This would get me through about 4 - 5 cartridges a day equating to about 72 - 90mg per day !!!!! This is probably how I managed to quit immediately the old cigs and move to a much more addictive equivalent without too much stress....... That is 72 - 90 mg of nicotine intack compared to about 35mg on normal cigarettes because I am smoking them the same. Now I have 2 choices, 1. Do not puff so much on ecig, but this will fail as I want a direct replacement or 2. Reduce the nicotine content in my cartridges. A quick calculation after a few days gives I smoke about 4 carts on average and need to replace 35mg of Nicotine for the normal cigarettes. So 35 / 4 = around 9mg per cart therefore = 9mg strength (or nearest) nico juice / cart strength. Simple calcs like this can save you loads of money and stop you overdosing or becoming more addicted to Nicotene. I hope this has helped. Admins, you might want to make this sticky for new users.