The Spartan was built initially by a disabled individual who wanted to be able to do weight-bearing gait training at home, down the longest hallway in the house, with his parents, brother, or sister. The vision was to have just one person do the complex task with him repeatedly several times a week as a form of intense home therapy and physical exercise.
And boy, did it work.
If your goal is physical health, then using the Spartan just 3-5 times a week for 20-30 minutes can do wonders for you. If your goal is neuromuscular re-education, then you will want to use the Spartan more frequently and for longer sessions. Something in the range of 5-6 times a week for 30-45 minutes will suffice.