One of the many benefits of this website is that you can train at a frequency which suits your lifestyle. As with any type of exercise, the more you do it, the better you will be. It is certainly recommended to practice with your partner at least a couple of times a week for at least an hour. Physical practice gives what is called ‘muscle memory’ when the body automatically goes to a position it has practiced a lot (this is like a guitarist, whose fingers goes to positions without even thinking about it).
All martial artists, however, will think about the movements throughout the day any time they get a break. Practice drills can be done alone any time you wish, even for only a minute at a time. Learning self-defense is a mix of mental repetition and physical practice.