Joe Offer wrote: For chorus songs, four to six verses can hold my attention. For ballads, I can handle a dozen verses, more if the singer is extraordinary.

The place where I am matters -- it's a lot easier to listen intently in a concert setting than to a recording. But I generally agree with Joe: a song in which something is actively happening can last a lot longer than one with no real action. If the action is sufficiently straightforward (so that there are no distracting sub-plots), and the tune is good enough that it doesn't get monotonous, a ten or fifteen minute song (i.e. one of several dozen verses) is OK.

It's important that there not be sub-plots or waste verses, though, because anything that makes you forget where you are in the song will ruin it.