Kimchi never goes bad; it just gets old. In Korea, Kimchi that is two to three years old is actually valued and eaten as it is or used to make other dishes as an ingredient. Some restaurants in Korea ripe Kimchi for years on purpose.
You can keep the kimchi refrigerated and enjoy it as often as you would like to. It doesn’t really go bad but it ferments faster and can create gas and bubble inside of the jar.