Frequency primarily deals with recovery. The quicker you recover, the more frequently you will be able to workout.
Your ability to recover largely depends on your current fitness level, age, diet, and work/life stress management. With the exception of age, all of these factors can be trained and managed.
To get started on the right path, focus on eating to fuel your body and getting enough sleep. Scale the workout down if you are tired or sore. If you feel your performance start to slip, take an extra day of rest.
Regardless of how frequently you choose to workout, ArmyWOD publishes new workouts five times a week. These workouts are designed to give you optimum time for recovery while maximizing work capacity over time. As your fitness level improves, you’ll be able to complete all five workouts as prescribed most weeks, and even begin to scale the workouts up.