Deepening the Perception of Impermanence

A Dhamma discussion based on the question..."While practicing I believe I can sometimes glimpse the impermanent nature of all determinations. For example, I can establish my mind on the impermanence of the breath and recognize that the breath depends on the body as its necessary basis which is in itself also determined by consciousness and thus also impermanent and not worth holding onto. This principle can be extended to everything in experience like the aggregates and sense domains.What would be the reason that this is still something I need to cultivate in order to recognize? When I stop the contemplation it seems like the mind hasn't fully understood this principle of impermanence thoroughly enough so that it cannot be seen in any other way any longer.Would you say this is just a matter of continued effort and repetition, so that at some point the mind will understand this principle 'all determinations are impermanent', or would you say that establishing the mind on this thoroughly for only one sit could be enough if this understanding sinks in deep enough?"