Hi Soosan,
I don't have a set prescription for how I mix it up. I usually do two-three of the S&H workouts a week, for example, legs and shoulders,AND triceps and biceps/once per week. I go very heavy and will up my weight when I am ready (now about every 3 weeks, before I was able to up once a week). I throw the pyramids in (up and down) for a few body parts per week. Sometimes, I will do the complete S&H one week and do the complete pyramids the next week. For the past 4 months, I haven't gone more than two weeks without doing S&H. I also do cardio including step, intervals, circuit, hi-lo and kickbox.