My son does the Regimen once a day and overall this seems to do the job for his mild to moderate acne, but he gets the best results when he does it twice a day. Once a day keeps his acne manageable but does not keep him clear. Unfortunately his early school bus schedule makes it hard to it in the morning, but we do try and play catch up on the weekends and longer breaks.
As the above poster says, it's different for everyone and you have to figure out what works best for you. Try doing it only once a day for the first few weeks and see what happens. Start out with a pea-size amount and work up to two full pumps. If two pumps once a day is enough to keep you clear, great! If this doesn't keep you as clear as you'd like, then try doing the Regimen twice a day. I do think it's a good idea to try to do the Regimen as directed until you're clear and then gradually cut back and see if you can get away with less BP and/or fewer treatments. Many on here find they can stay clear on less but it does vary for each person. Also, if you can live with a few pimples in the interest of fewer treatments, then great!
Good luck with whatever you decide! 
I have been using the BP for a week now just once at night and I'm completely clear! It's miraculous! I got really flaky from Day 5ish and I could not stand it so I tried the AHA+ without waiting for a month. It didn't sting as much as I've expected but my face stayed red for 2 days. Since my flakiness had been really bad especially around my mouth area it took 3 days for me to get rid of it completely. I mixed my moisturizer and the AHA+ to a 1:1 ratio. My skin is radiant now and I just have just a couple of hyperpigmentation that I feel are fading away everyday! I love it!