Everything changes. That knowledge is a tool, not a threat.

In Buddhism (anicca), impermanence is one of the three marks of existence: all conditioned phenomena — thoughts, feelings, relationships, bodies, civilisations — arise and pass away. Clinging to what passes is the root of suffering. In Stoicism, impermanence is framed differently: everything outside your control — people, possessions, reputation, health — is "on loan," subject to being returned. Marcus Aurelius frequently contemplates how quickly people and empires are forgotten. Both traditions use impermanence not as a reason for despair but as a reason to stop placing your wellbeing in what cannot hold it.

The mechanism is expectation: much suffering arises not from what happens but from the gap between what happens and what we expected or demanded. When you genuinely hold impermanence in mind — not as an idea but as an active awareness — the expectation that pleasant things will last changes. Loss becomes less shocking; endings are anticipated rather than surprising. Buddhist practice calls this "the second arrow": the first arrow is what happens to you; the second is the suffering added by believing it should not have happened or should have lasted longer. Understanding impermanence removes the second arrow.

No. Both Stoics and Buddhists planned extensively — Marcus Aurelius ran an empire; the Buddhist tradition built elaborate monastic institutions. The difference is in the relationship to those plans. The Stoic phrase is "amor fati with reservation": you make plans, pursue them with full effort, and accept whatever the outcome is. The Buddhist frame is "non-attachment to outcomes": you do the work without grasping at a particular result. Neither tradition recommends not acting; both recommend acting without making your peace conditional on a specific outcome.

The classical technique is "negative visualisation" or "momento mori" — briefly, deliberately contemplating that what you value (a relationship, your health, your ability to do work you love) will not always be present. Done for a minute or two, this typically produces gratitude rather than dread: you notice the current reality more clearly when you have briefly imagined its absence. The practice becomes morbid only when it is prolonged into rumination or used to justify inaction ("why bother if it all ends?"). The correct use is the reverse: to motivate engagement with the present because the present is what you have.