`@classmethod` vs `@staticmethod` vs instance method?

class User:
    _count = 0

    def __init__(self, name):
        self.name = name
        User._count += 1

    def greet(self):            # Instance method
        return f"Hi, {self.name}"

    @classmethod
    def from_dict(cls, data):   # Factory — dùng cls thay vì User
        return cls(data['name'])

    @staticmethod
    def validate_name(name):    # Utility — không cần self/cls
        return len(name) >= 2