Are you better off having, say, two 20 minute sessions or one 40 minute session?
In general, the longer the session the greater the benefits, which means that a longer session should be better for you than two (or more) shorter sessions, even if the total minutes are the same.
For a start, it can take 5 - 10 minutes for your body to really relax, and it's only when that happens that you start getting the maximum treatment benefits.
It's kind of like sleep. When you sleep through the night, it's the deep or "rapid eye movement" sleep that does you the most good. Similarly, longer treatment sessions on the BackHug help unlock the deep back therapy benefits.
On the other hand, regular treatment is like maintenance for your body. When you're busy and time is scarce you may not have the luxury of being able to lie down for a long treatment session. In that case, it's better to grab short treatment when you can than none at all.