You can watch the evolution of special effects in movies, if you like, but the passage of time is clearer if you listen...and consider how you listen.
When the original Star Wars came out, my parents were in college. They went to the theater several times to see it, and bought the soundtrack on vinyl. They played that record only once, to transfer the music to a cassette tape, so that they could listen to it without wearing out the vinyl. I listened to that tape dozens of times as a child.
When The Phantom Menace was released, I was in middle school. I saw it in a matinee, and afterwards, on the very same day, I took a gift certificate to Tower Records and bought the soundtrack on a CD. Years later, I ripped the tracks onto my laptop.
Most people who own the soundtrack of The Force Awakens--if they even purchase it!--will never own it on any physical medium.