To me, it depends on the situation. Recording - usually under. Time is often money and I go for something that fits and serves the song first. But in my trio, where I'm the only guy besides bass and drums, I'm pushed to keep things interesting for 4 hours. It's a challenge that pushes me to experiment and try things that might be beyond my ability to do well. Stretching is good for me and, fortunately, the audience is usually accepting.