The level is subjective
How many times do you hear that!? I'd suggest starting about around 6 to 7 watts and go up or down from there. Or 3.8 to 4.0 Volts then again go up or down.
Now you need to get an
istick so you can have a backup for the backup LOL
I am about a week or so into the iStick and it is simply awesome. I am going all day at work without a single recharge. The eGo VV2 I had would need to be charged about 2-3 times during the day and this iStick is shorter that the eGo albeit it is wider but it fits so nicely in your hand it is not too wide if you know what I mean.