The pads will last about 2 hours and the fuel cartridge will last about 6 hours or so. I cannot smell it when it is on, but if you play the wind right the deer won't smell it either. If you are not playing the wind right the deer will smell you anyway. Also if the skeeters are out, you will be fidgeting a lot more anyway and the deer will definetely see that, with the thermacell there will not be any skeeters by you.