All In The Packaging

Recorded music no longer has the constraints it once had. But over the past two or three decades, we have been nostalgically reintroducing the old formats with the original constraints--for example a digital release with 12-15 songs as would fit on two sides of a vinyl record. 

I like the idea of serialization, and that may be the format going forward. If The Beatles' Sgt. Pepper or Dark Side of the Moon were made today they probably would have been serialized. Conceptual work, by nature, is open-ended because very often the subject matter is evergreen and is in the flow of life. TV and film have always been in the feedback loop between quotidian life and the time frames in works of fiction--but music less so because it has been more tethered to the medium.

It's important to have constraints, but they don't necessarily have to be in the media itself. What you want is a constraint that works in the flow of human attention. One of my rules of thumb is to create some kind of change at around 2:00-2:30 into a piece of music, especially if it is repetitive in nature. (This was 10 years ago. It's probably 1:00-1:30 or even less now). What IS in the media is attention span, which is driven by how the music is packaged. It's interesting when you think about things using the "package" metaphor because it controls behavior more than we think. (I like the double meaning of that...)