The path to achieving Pratyabhijna, or the recognition of the self as Shiva, is a deeply personal and individual journey. It is not something that can be achieved within a set amount of time, as it is a continuous process of self-discovery and realization.

The time it takes to achieve Pratyabhijna varies for each individual, as it depends on their level of spiritual maturity, dedication, and understanding. Some may experience a sudden recognition of the self as Shiva, while others may take years to fully understand and embody this concept.

The first step towards achieving Pratyabhijna is to develop a deep understanding of the concept of Shiva and the nature of the self. This can be done through studying ancient texts, such as the Shiva Sutras and the Kashmir Shaivism scriptures, and through the guidance of a spiritual teacher.

Next, one must engage in practices that help to purify the mind and body, such as meditation, yoga, and self-reflection. These practices help to quiet the mind and remove any obstacles that may hinder the recognition of the self as Shiva.

As one progresses on their spiritual journey, they may begin to experience glimpses of their true nature as Shiva. These moments of realization may be brief, but they serve as a reminder of the ultimate goal of Pratyabhijna.

With continued dedication and practice, one may eventually reach a state of constant recognition of the self as Shiva. This is known as the state of "Sahaj Samadhi," where the individual is in a constant state of awareness and oneness with Shiva.

However, it is important to remember that the journey towards Pratyabhijna is not a linear one. There may be setbacks and challenges along the way, but with perseverance and faith, one can continue to progress towards this ultimate goal.

In conclusion, the time it takes to achieve Pratyabhijna is not something that can be measured in days, weeks, or even years. It is a continuous process of self-discovery and realization that varies for each individual. With dedication, practice, and guidance, one can eventually reach a state of constant recognition of the self as Shiva, and experience the ultimate bliss and oneness with the universe.