The preceding three rules of thumb can be used as a guideline to determine whether or not you should or could use a struct. Of course, there are other reasons why you would or wouldn't use a struct, but it's considered best practice to use one whenever possible. The main reason for this is the way it handles immutability. As you saw, structs are a lot stricter about mutability, and many programmers consider this a good thing because it makes their code more predictable and safer.