When do you use ser vs estar?

Answer 1

To add a bit more, some adjectives change meaning, depending on which verb they are paired with. For example,

Estoy listo = I'm ready.

Soy listo = I'm smart.

Estoy aburrido = I'm bored.

Soy aburrido = I'm boring.

Answer 2

Here are some examples to further help you understand Heather's excellent explanation:

 

Ser-To be

 

1. Yo soy un estudiante. I am a student.

2. Nosotros somos amigos. We are friends.

3. Ella es amable. She is nice.

 

Estar-To be

 

1. Yo estoy en casa. I am at home.

2. Tu estás nervioso. You are nervous.

3. Uds. están enfermos. You all are sick. 

Answer 3

First off, great question! Estar is always used to describe temporary states, such as emotions, locations, etc. Ser is always used to describe permanent states, such as personality traits and times of meetings.