These simple and short recordings, often based in breath, give you an opportunity to use them almost anywhere. Seated in a chair, lying down, in a car, etc. That said, treat them as a break from the day. Make the time special for you, you deserve it. Note there are some short specialty recordings here as well, to use in a tough moment, or to shift your response in a specific environment.
These recordings begin to allow for a deeper physical relaxation response. These give the physical body more time to integrate the benefit of the deepening breath. Again, make sure you create the proper space for yourself. You may find specialty recordings and favorites which help you build a consistent practice.
These longer recordings will create a deepening relaxation response and therefore the body/mind will begin to receive the benefit, which you will notice. At this length you begin to receive the deep sleep benefits. Similar to brainwave shifts that occur at night while sleeping. You receive up to a 3 to 1 benefit ratio; 20 minutes of these recordings are equal to 45 minutes to an hour of nighttime sleep.