How to know when to use 'ser' and 'estar'?

In english 'ser' and 'estar' are both translated as 'to be', but are used differently. 'Ser' is used when when it's a permanent reality, for scenarios that are always true and don't depend on any circumstance. For instance, 'las verduras son saludables' meaning 'vegetables are healthy' and 'Carla es simpática' meaning 'Carla is nice'. In both cases, as the verb ' ser' is used, are facts that are always true. On the other hand, 'estar' is a punctual fact, something circunstancial and occasional, that doesn't have to be always true. For example, 'esta comida está deliciosa' meaning 'this food is delicious' and 'Carla está simpática' meaning ' Carla is nice', but in this case, Carla is nice in this particular moment, not always. Moreover, 'estar' is also used for location and temporary states: 'Juan está en el médico' and 'ser' when describing a quality, a job, a physical or emotional state: 'Juan es médico'.