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Using single inheritance, a subclass can inherit from only one superclass. Continuing the example given above, a Person object can be either a Student or an Employee, but not both. Using multiple inheritance partially solves this problem, as one can then define a StudentEmployee class that inherits from both Student and Employee. However, in most implementations, it can still inherit from each superclass only once, and thus, does not support cases in which a student has two jobs or attends two institutions. The inheritance model available in Eiffel makes this possible through support for repeated inheritance.

The inheritance hierarchy of an object is fixed at instantiation when the object's type is selected and does not change with time. For example, the inheritance graph does not allow a Student object to become an Employee object while retaining the state of its Person superclass. (This kind of behavior, however, can be achieved with the decorator pattern.) Some have criticized inheritance, contending that it locks developers into their original design standards.cite-ref-holub-20-0[19]

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