re: Workout board: how many days a week should you lift?

Yes.

The only things I see varying in the phases, are

- number of reps (I´ve seen earlier phases are 13-15, 10-12, 8-10)
- rest between sets (varies from 45, 60, 90, 12, 180 seconds)

It´s a very fast workout. I normally work the hell out of a muscle group, and don´t revisit it for two days.

In this one, each muscle group gets only three sets of one exercise, and a fourth of another (trying to pick up the next time around with three that complement that fourth, and add a new fourth, and so on).