Let's start with the different between principle and technique. Technique is way of doing something in a specific manner. Principle is a generalized pattern that can be applied in a wide range of situations. In soccer, to probe the defense of the other team is one principle. A technique for doing so would be to move the ball among your own players until you perceive a weakness in the opposing team's defense, such as a person who moves more slowly, or who leaves open space between him and the other players. The passes necessary to probe the defense need to be precise and quick, which is, again, a matter of technique. The ability to apply a principle in a given situation depends on the skill or technique of the players. If there is no technique, understanding the principles won't help much.
A teacher taught her students how to write the numbers from 1 to 10. One young boy seemed to be having difficulty writing the number 1 but when the teacher looked at his work, she could not see a problem. "Good," she said, "you can write the number 1. Now start writing the number 2."
"It isn't right," he said, and continued writing 1's on his slate.
Eventually the teacher became impatient because he was holding the class back. "Off you go," she said, "and come back when you feel you have it right."
Several weeks later, the boy returned to the classroom and said to the teacher, "I think I have it now."
"Okay," she said, "go up to the blackboard and write the number 1."
The boy went up to the front of the class, picked up a piece of chalk, and wrote a large number 1 on the board. As he finished, there was a loud crack and the blackboard split in half.
Mindless repetition does not train technique in and of itself. Technique training consists in repetition and learning from each repetition until the technique is right there. For instance, in the Locket Mahamudra tradition, there is a technique for placing attention on the breath. When you have trained this technique, attention goes straight to the breath and rests there, cutting right through distractions -- a bit like the young boy writing the number 1.
Another misunderstanding, somewhat related, is the difference between training in movement and training in facility. Take reading, for instance. Most of us don't even remember learning how to read, but, it's probably a safe bet that in the beginning, we spent quite a bit of time spelling out the words and making the sounds. Our parents or teachers would correct us. Bit by bit, we learned various words, how to sound them and what they meant. But then something strange happened. We stopped thinking about how to sound them. We even stopped thinking about what they meant. We just read, and we could understand the meaning of what we read. We had developed the facility of reading. Now higher levels of learning became possible. We could notice and appreciate the rhythm of the words, the allusions, the metaphors, the lines of argument, etc., and our skill in reading became increasingly more sophisticated.
Many people, when they practice mindfulness in daily life, say, do normal activities slowly, so they can put their full attention on the activity. This is analogous to sounding out words when we read. It is not doing things mindfully. It's training in mindfulness. It may be a way of training the initial ability, but it is an ineffective way for negotiating the exigencies of life, just as sounding out words is an ineffective way for reading a novel or a contract. Yes, we have to become conversant with the vocabulary of mindfulness, but that is only the beginning, not the end. We haven't trained mindfulness until we can go about our day as any other person would, except that we bring a consistent quality of attention to everything we do.
A possible comparison is tai chi. In tai chi, one does the movements very slowly so that the body, right down to the level of the sinews and tendons, knows the movement. But in execution, one does not move slowly. The body is trained so deeply that the movement happens without thought, without even a first thought.
In addition, when you go about your life doing things slowly, you may actually be suppressing patterned reactions. The attention that goes into moving slowly blocks the patterns and you don't have to meet the material locked inside. This, of course, is a form of repression. When you move at a normal pace in your life, patterns of reaction arise. Practice in daily life means that you bring attention to the pattern as it arises, not to block it, but to experience it completely, the body sensations and impulses, the complex of feelings and the various stories that sustain and propel its operation. When you can experience all that and not fall into confusion, then you are beginning to live in attention.
In vajrayana, people engage in mantra repetition in much the same way. That, they have been told, is what it means to practice all the time. But that is just repetition. Nothing is really being trained, not even technique. The purpose of the repetition is to replace the habitual undercurrent of thinking in the mind with the mantra. Many people use it to block thinking. For it to replace thinking requires a consistent attention to the sound of the mantra, not just mindless repetition. When the mantra has replaced the undercurrent of thinking, you have a quiet mind, and continuous practice now becomes possible.
Many of the misconceptions about continuous practice arise because methods developed for monastics and anchorites living in pre-industrial societies have been unthinkingly taught to people like you and me who live in complex post-industrial societies where principle is often valued more than technique. In the medical profession, for instance, the adage for a new medical procedure is "See one, do one, teach one." This is hardly a way to develop mastery in technique and this kind of problem permeates our culture.
In my business consulting, I once helped develop a robust team subculture based in collaboration, open communication and cross-functional teams where the dominant culture was authoritarian, secretive and communication was restricted to silos. How? By training the team I was working with in basic meeting skills: starting and stopping on time, setting an agenda, being clear about who was responsible for what actions, etc. As those skills became instilled in them, a different culture developed on its own.
In order to practice all the time, we need to instill different behaviors, and to do that, we need to train in technique -- doing something over and over again until it becomes part of us. The ability to control and predict a wide range of phenomena has given us the illusion that we can control what we experience in our lives by an act of will. We feel we should be able to decide to be a certain way and everything will follow. But it doesn't work that way. On the individual level, we end up repressing patterns of emotions that return in unpredictable ways when we encounter difficulties.
Practicing all the time is a result, not a method. It is a result of making specific efforts at the level of technique so that those techniques become part of you and the way you relate to the world. It takes time to change behaviors. If you try to do too much too quickly, you end up repressing unresolved emotions and subjecting your mind and/or your body to more strain than they can handle. One of the signs of too much strain is increasing rigidity, and if you go to far down that road, something in you will just break and it may or may not be reparable.
On a related topic: Several people have asked me recently about pushing through physical difficulties in the practice of prostrations. I've had my share of physical difficulties, and I had great difficulty at various points finding a way forward. People vary tremendously, and some people are able to push through difficulties. For other people, that approach doesn't work and can be quite harmful. What I've come to is this: follow your heart and listen to your body. In other words, let your body and heart work out the right approach for you, and take your conceptual mind out of the mix. When you follow your heart, you follow your intention. Your body knows what it can and cannot do. And the two can understand and talk with each other in a way that the conceptual mind cannot fathom.
You might consider that working with heart and body together is a good way to practice in daily life. The effort requires attention to what you are feeling and what you are sensing in your body, and you begin to function from something other than the conceptual thinking mind.