I use it about once every few days and it works like a charm. You have to be patient and resist the urge to kill the roaches. I have never had a big infestation but for me I see results in a few days. I have moved 4 times and have had to use this product every time. This move I have decided to treat every week for a month to hopefully get rid of any bugs forever. I've had a case where they came back after many months later (I was living in an apt so it could have been neighbors) and this go around I found a dead roach in the bathroom recently (after my first treatment) so I just want to be very sure they are gone gone.