Is "each night" interchangeable with "every night"? If different, how are they different?
Answer from a Native speaker
"Each" and "every" are similar since they both refer to something which is singular but they are not always interchangeable. "Each" refers to an individual object or person while "every" often refers to a group of objects or people counted together as one. However in this case, "each night" means the same thing as "every night" and so "each" and "every" in this context can be used interchangeably. Ex: She has a bracelet on each wrist. Ex: Every house on the street has a chimney.