Experience usually pays off, whether you are talking about martial arts or other parts of life
The truth is that enhanced proficiency, understanding, confidence are all the result of practice. While most people will acknowledge that this is true, many people fail to put in the necessary time to yield positive results.
Those who wish to become truly skilled a their martial art will need to practice to the point that the movements are as natural as any other task we have been doing for years, tying our shoes for example. You will not achieve this level of skill by attending classes a couple of times a week. The work that you do away from class on your own is what will bring you to a level of mastery. To really grasp what we are learning homework is necessary, no matter what we are studying. This practice must be in addition to the classroom experiences where we are first learning the skills. It is the constant repetition of these new skills that will allow us to truly master them. Practice will allow us to recognize our flaws, correct them, and reinforce the positive.
Each technique in a martial art needs to be practiced to the point where it is second nature and can be done without the need for thinking. Basic skills need to be drilled over and over and over. Your instructors will be able to see who has practiced and who has not based on how the body moves, the questions that people ask, and how people are able respond to corrections that the instructor makes.
Instructors have come through the same path as their students. They have faced the same challenges to regular practice including pressures from their jobs, family obligations, limited time to practice, and limited space to practice. They have often made some of the same excuses for not practicing that you have. Many people hope that this will cause their teachers to stop pushing them so hard to practice at home.
The truth is that your teacher also knows that there is no way to master the skills with just a few short hours a week of class. They also know that you have stated that it is important to you and that this type of training can save your life or the life of a loved one. While most of us will never need to use the skills we learn in the martial arts for self defense the truth is you never know when the moment where you need mastery is coming. Do you really want to be a black belt and not have the skills necessary to protect your life and the lives of those around you?