Because we habitually identify with the fabrications of the mind, we do not find the clear light during sleep. For the same reason, our waking life is distracted, dreamy, and unclear. Rather than experiencing pristine, non-dual rigpa, we remain trapped in the experiences of fantasy and mental projections.
Yet awareness is continuous. Even when asleep, if someone softly says our name, we hear and respond. And during the day, even when most distracted, we remain aware of our environment; we do not simply fall down insensate or walk into walls. In this sense, there is always presence, but the awareness, though unceasing, is foggy and obscured. Piercing the obscurations of ignorance at night, we enter and abide in the radiant clear light. And if we pierce the delusions and hazy fantasies of the moving mind during waking life, we find the same underlying pure awareness of buddha-nature. The distraction of our daily life and the unconsciousness of sleep are two faces of the same ignorance.
The only limits to practice are those we create. It is best not to compartmentalize practice into periods of meditating, dreaming, sleeping, and so on. Ultimately we must abide in rigpa completely in all moments, waking and sleeping. Until then, the practice should be applied in every moment. It is not that we must do every practice we learn. Experiment with the practices, try to understand what the essence and method of the practices are, then discover which practices actually further development and do those until stability in rigpa is attained. The components of the practice are provisional. The position of the body, the preparations, the visualizations, even sleep itself, are not important once one directly knows and abides in the clear light. The experience of clear light is reached through the particulars of the practice, but once it is reached there is no need for practice. There is only clear light.