Munindra-ji used to say that in spiritual practice, time is not a factor. Practice cannot be measured in time, so let go of the whole notion of when and how long. The practice is a process unfolding, and it unfolds in its own time. It is like the flowers that grow in the spring. Do you pull them up to make them grow faster? I once tried to do that with carrots in my first garden when I was eight years old. It does not work.
We do not need any particular length of time for this process of letting things be.