With one doorbell, two properly placed outdoor cams and two indoor cams — five total — you'll get great coverage for your home. We can't give a definitive number without seeing your individual layout and square footage, but you should be able to extrapolate a number from the above information. Some outdoor cameras have their own sirens to scare intruders, which we appreciate for our deterrence-first policy. Indoor cameras may have a built-in siren, or more likely will send an alert to its home h...