I know if I used it twice a day my skin would be so much better and completely clear. But I've only ever used it twice a day for a short amount of time - In those times, my skin (acne) was a lot better but the dryness was a bit too much for me to deal with, and I couldn't apply makeup over the top of BP and dryness. Also, I use the regimen, so that can take quite some time to do all the steps and wait for it to dry etc and I don't have the time in my mornings to do that everyday. So I just apply the regimen at night - it's my only option really.
I know there are people who use BP once a day and that works perfectly for them - your skin could be like that too So if you want, just try it once a day and then if you feel you need to use it more often, you could start that and see how it goes.