When one thinks of renunciation, often it is framed as an external behavior or process. The person who is in the process of renouncing gives up his or her material things, and in Buddhism they cut their hair, leave their home and join a group of other renunciates. Furthermore, upon being ordained, the renunciate further commits to renouncing certain behaviors, thoughts, and/or actions. In so doing, such a person is choosing to invest in conditions that are conducive for their devotion to the spiritual life. The renunciate participates in both a physical/behavioral and a symbolic renunciation (ie. cutting of hair).
However, it seems to me that what is most important is the intention of the renunciatory process. In other words, for what purpose does the individual renounce? What does such renunciation mean?
When you have nothing to keep, nothing to gain, no possessions, it is harder to be tempted by the idea that accruing any material good will lead to some sort of lasting happiness. Renunciation then comes from the recognition and dis-identification from material goods and social status as a means to satisfaction. For the Buddhist renunciate this is clear.
Here is the distinction though: one does not need to become a monk, or give away all of one's possessions to practice renunciation. Why is that? The heart of renunciation is the recognition that we can't keep anything, and furthermore the compulsion that drives us to want to keep, accumulate, regenerate, or recreate past experiences is actually what produces predictable and cyclical dis-satisfaction. In this context, renunciation is the renunciation of the hope that anything, any experience that is created or generated can be ultimately fulfilling. The belief that such material things or specific experiences that come and go will give us fulfillment is based on the delusion that there is something we can hold on to.
When renunciation is sincerely practiced, there is the recognition that the greatest virtue and meaning within our existence is being able to show up and be of service to other people, which we might say is the bodhisattva principle. When there is nothing to hold on to or accumulate, being of service without expectation for any gain is natural. When you really know that you have nothing to keep and that you can't really keep anything, you simply attune to the process of giving it all away. In that giving, you actually receive the gifts of compassion, generosity, and a nourishment that has no value. However, we can't keep these gifts either. Rather, if we are practicing renunciation, we simply keep giving them away. This is generating positivity.
Furthermore, what we receive when we are practicing this form of renunciation is our own enlightened mind. That is because our enlightened mind does not need anything. It needs nothing. It is totally free from the need for anything. Our enlightened mind can't hold on to anything, because there is no thing to ultimately hold onto or to be held. It sees through the appearance of "things" produced by conditions, and into the emptiness of all appearances.
Therefore, it is important that we truly understand the heart of renunciation. In the context that I am talking about, such renunciation is seeing through the idea that anything, experience, circumstance could be ultimately fulfilling. Sure we can be relatively fulfilled by accomplishments, actions, etc- yet true renunciation is the recognition that ultimate fulfillment is not predicated on achievement, gain or loss, accumulation of merit or experience. Therefore, it is important to adjust our expectations. If we expect to be ultimately fulfilled by relative experiences, material things, accomplishments- according to the Buddhist view- we are misunderstanding the nature of suffering and true fulfillment. We are not yet practicing the heart of renunciation.
Thus, it does not matter if you are a monk or a rich person with a mansion and a million gadgets. If you are a monk and are expecting some kind of ultimate fulfillment from an experience or some object, then really you have misunderstood the heart of renunciation. Similarly, you could be a rich person and recognize that your material goods bring you no ultimate fulfillment. In such case, practicing renunciation might involve using your resources in a way that serves other beings so that they may suffer less- in which case you have understood the heart of renunciation.