If I began on today April 18, it would be in Don Quixote, according to the guide and I would learn how the naming came about. So I would know 15 minutes more than I knew 15 minutes ago.
And here is an English professor who tried it and found it quite useful.
“I discovered that a reading regimen, even if only 15 minutes a day, requires discipline. William James wrote that discipline is needed in the formation of any new habit. In this case, the habit was reading regularly and outside my comfort zone. I often had to fight against an inclination to skip a day. But the relative brevity of the selections kept me on track—a hint to teachers who assign too much and thereby encourage cribbing and cramming. With a 15-minute assignment, I could push on, knowing that the end was near.” Paula Marantz Cohen, WSJ, Dec. 26, 2014