At the beginning of his Enchiridion, Epictetus gave the advice that went on to guide so much of Stoic practice:
Some things are within our power, while others are not. Within our power are opinion, motivation, desire, aversion, and, in a word, whatever is of our own doing; not within our power are our body, our property, reputation, office, and, in a word, whatever is not of our own doing.
The dichotomy of control tells us what depends on us and what doesn’t. Per Epictetus, the only things we are in complete control of are our judgements and our actions. Everything else in life – including things like wealth, health, and other people’s opinions – depend to some extent on external circumstances. We can try to influence these things but ultimately we do not have complete control over them.
It can be easy to fall into old patterns, however, and try to change things that we ultimately have no influence over. Sometimes we need a quick reminder so that we can reset our focus and spend time on the right things.
For a full explanation of the dichotomy of control, check out this short explainer. For your future reference, here is a cheatsheet to remind you what is and isn’t within your control.