Concerning Fidelity in Design | UX Booth

Using a method too high in fidelity wastes resources (both time and material) and risks a mediocre path being selected because better options were never given a chance. Working at too low a fidelity, on the other hand, means that the details never get filled in, yielding a half-baked result.
(Link: Concerning Fidelity in Design | UX Booth)