In which case would I use the verb SER and in which case would i use the verb ESTAR when talking about someone's profession?

The verb ESTAR is used when the job is considered temporary or relatively unimportant to the person undertaking it.-Mi prima va a estar de camarera en un restaurante todo el verano.-My cousin will work as a waitress in a restaurant during the entire summer.In this case it is clear that for the speaker's cousin, this is only a temporary job for the length of the summer. On the other hand when you are simply referring someone to someone's everyday profession you would use the verb SER, reflecting the permanent nature of the job. -Mi padre es abogado (My father is a lawyer).-Soy estudiante (I am a student).