"Even" as in widespread, commonplace, everywhere, ubiquitous. IMO, Jon has it right in this post. Today, if you want to be a pro, you need at least a usable, reliable three octave range -- and in many cases much more. I'm a comeback player. Prior to last summer I hadn't touched a horn in almost forty years. I'm certain I'll never play professionally but I'm having a great time playing again. My range is increasing incrementally and I'm really surprised and pleased at how easily my sight reading came back. In that respect, it's almost as if I never quit. I had the benefit of advanced level courses in music theory and harmony from excellent teachers to thank for that. IMO, Al has it right too. If your goal is to practice all day then by all means keep jogging. If your goal is to increase range and endurance then you have to have a regimen focused on increasing range and endurance. Even distance runners have to sprint to the finish line.