In the beginning of my training, I myself had the wrong idea about learning karate, and I'm sure that others will sympathize with me. I would focus all of my energy on one concept or idea trying to perfect it by doing as much of it that I could during that moment. However, once the pressure was off, I would drop it to the side, and put my energy towards the next challenge. I guess that my energy was towards meeting the various requirements towards my next belt rank test. However, this kind of training does not help improve one's memory of the lower basic foundational movements which support the higher requirements.
Our bodies, and minds need to cover the beginning material properly over and over again with much focus as we advance in knowledge. This builds up our abilities, and strengthens our understanding. Too often I have seen a higher black belt stopped in his/her tracks by a simple beginner movement because they had been focusing only on improving a higher kata.
How our minds work:
"The fact that repetition helps you to memorise is well known, but the importance of the time between repetitions is less well known.
The timings are particularly important because if you don’t revise often enough you will forget things. And if you do it too often (especially in the early stages) you’re going to be wasting a lot of time, and confuse yourself.
....Breaks are incredibly important because your brain needs time to fix itself and recuperate. You may think that your understanding of what you’re studying is highest immediately after you finish studying. In actual fact, you will have a greater understanding following a 10 minute break!
Why is this?
Well, when we create a new connection in our brains, that connection is weak. Over a period of about 10 minutes, it gradually strengthens and becomes more stable.
If you don’t take enough breaks, those weak connections interfere with other new connections and you become confused. So you need to give your brain enough time to make those connections strong. When they are strong, they will be able to handle any interference.
After that first 10 minutes, your brain cells will reach their peak strength. At this point you will know the subject better than you did when you started your break.
Unfortunately your learning then begins to fade again.
The new connections begin to weaken again until they finally disappear. If we don’t do something about this, we will forget a lot of what we’ve learnt.
We stop the degrading process by repeating (or revising) what we previously learnt. This fires off the connection in the brain again, and makes sure it stays strong.
So when you’ve finished revising, take another 10 minutes break and then revise again. And then do the same thing a 3rd, and final, time. Experiments have shown that 3 activations, with 10 minute breaks in between, make the memories the strongest and last the longest." taken from Improve Human Intelligence
Revision has to be ongoing to maintain the information, but each person has a different "need" for the amount of revision necessary to keep the information strong in their minds. I would suggest that it is a safe bet if beginner basics is included in one's personal training frequently. They can be useful as a "warm up" if done in slower speed, and with less power.
A Sensei can incorporate this concept of how we memorize into their lessons. For example, teaching a pattern to a student. It may be to the student's benefit to segment the instruction into shorter 10 minute periods interspersed with a more familiar exercise/activity to give the mind a "break". These activities can be similar, and supportive to the movements of the pattern, or just random conditioning exercises such as squats, sit ups, push ups, etc.