I love it. You just apply when you start to feel one coming on and it zaps it before it shows up. It mainly works on the larger, hormonal acne which was my issue. Usually it takes only 3 times every 4-6 hrs or so, but on stubborn ones, I'll do about 5 unless it's gone. Walgreens now sells replacements for a discounted rate, and sometimes on sale on top of that. I would highly recommend it unless you have severe acne.