What constitutes a full set?

Transmogs with many pieces coming from the same set are often a bit looked down upon as ‘low-effort’. In your opinion, how many pieces need to be coming from different sets before a transmog is no longer considered to be low-effort/a full set? Do only the main armor slots (head, shoulders, chest, wrist, gloves, waist, legs and boots) matter, or do you also take weapons, cloak and tabard into consideration?