Here is a quote from http://www.psychologytoday.com/blog/memory-medic/201201/cram-or-not-cram-is-the-question:
In most situations research has made it abundantly clear that spacing the learning over many shorter sessions is much more effective than trying to do it all in one big session. Surprisingly, longer intervals between learning sessions are more effective than shorter intervals.I plan to do a lot more posts on this topic, but the article linked above is good place to start if you not sure there is any Science or data to back up the idea that sometimes less can be more.
That article is also good place to start to understand why I urge people to have a rotation of practice, watching replays/VOD, and non SC2 days like exercise & fun activities. For more on my thoughts about that see http://cliffsesportcorner.blogspot.com/2011/11/starcraft-2-skills-planned-structured.html
Some people have wondered how Stephano improved so much with "Only 3 hours" of practice. This is part of the answer, I will cover other parts in future posts.
To see more of my posts about this topic click http://cliffsesportcorner.blogspot.com/search/label/Starcraft%202%20Skills or any of the labels at the bottom of any post or the label cloud at left of blog. The labels are a subject or Index list of topics.