Rock, pebbles, sand, water

I'm actually learning japanese on my own.
So basically, i dl-ed some ebooks and tried to sieve some good info from them.
Fascinatingly, I came across an article on time-management.
The author was actually sharing his views on how to spend just 10 min a day reviewing new jap words.

So here I quote:

Here's an interesting analogy I found on the Internet on managing your time:
(by James R. Beach)

A professor walks into the room carrying an empty 10-gallon water jug and dragging an obviously heavy bag. He places them on the teacher's desk. Without a word, he begins placing white rocks, just big enough to fit through the mouth of the jug, into the jug until they reach the very top.

"Is it full?" he asks. The class nods.
"Maybe not," he says. He then stuffs tiny pebbles into the jug and the pebbles find their way through the cracks in the rock. "Full now?" he asks. The whole class nods. He then shovels sand into the jug, occasionally shaking the jug, and the tiny grains sift through the rocks and pebbles. "OK," he says, "now is it full?" The class nods in unison. He smiles. He then slowly pours water into the jug until a water glass is finally empty.

"The lesson here," he says, "is that there is always more room in our lives than we think there is. When you think you're out of time, there is still more available if you look for it."

Here's the time-saving payoff:

The ROCKS are the important things we have to accomplish regularly to be successful. They go into our "time jug" first, because they are most important.
The PEBBLES represent those things we may not like to do, but we must do. They go in next. The SAND represents things that we should do, we may even like to do, but they're not as important.
The WATER represents the few remaining things that make a difference.
If you reverse the order, putting in the water, then the sand, then the pebbles, there will not be enough room for the rocks. So prioritize your activities and make sure the rocks go on your schedule first.

That's all from the book.
I have seen some brilliant articles on time-management but none came across so simple yet effective, using pebbles and crap.

Brilliant analogy I would say.
I'll save it for my kids.