To understand naskh (supersession), distinguish simultaneous contradiction from a change in the rule applicable at a later stage. Two opposed commands for the same persons, time and conditions would be contradictory. Different prescriptions for different stages need not be.
A physician may prohibit a food during an acute illness and allow it during recovery. Each instruction can suit its situation; the second does not prove that the first was wrong from the outset.
This analogy clarifies the conceptual point, but establishing an actual instance of legal abrogation still requires reliable scriptural evidence, not personal convenience.