I have't actually counted refills, but I find them to last about 2-3 days of non-exclusive use (alternating between it and a regular atomizer). I love these cartomizers (the flavor and vapor are better than with an atomizer), but I'm experiencing a high failure rate. None have actually been DOA, but one only lasted a couple minutes before it stopped working, another lasted a couple hours and the one I'm trying to use right now seems to have some sort of air flow blockage. Basically, I think these are awesome when they work, but since they fail so easily, they end up being more expensive than regular atomizers.