Aladar,

One of the groups of people we all seem to have admiration for are the Beatles. Most of all of their songs were in the neighborhood of under three minutes. It actually was not up until the drug addled 60's that time frames on songs went much past that. And that was due to the invention of the long playing record. Most records up until then were 45 rpm singles. The music industry basically has reverted to those days.

As Jim says, rock does tend to have a little more leeway in intros but those are often part of the make up of the band as musicians. I am looking at things from a song perspective and that of most contemporary radio, which is the main way the majority of publishers, record labels and people involved in the industry look at things.

Always write what you want but try to look at it from your audience's point of view. Write a lot of songs and always keep moving forward.

MAB