A genuinely flexible, increasingly common approach that sidesteps the warm/cool question entirely.
Mixed-metal pieces vary widely; the individual metals within them follow their own finish behaviour.
Mixed-metal or two-tone frames are increasingly available and follow the same logic.
No metal tone is objectively 'best' for any person — this is a description of typical visual effect, not a ranking.
Mixing metals is itself a practical way to avoid needing to choose just one — a genuinely valid alternative to picking a single 'correct' metal.
Understand your undertone before comparingWorks with most palettes precisely because it doesn't commit to one temperature.
Mixing metals works because each metal's reflectance spectrum is different, and the eye reads the differences as deliberate contrast when they are repeated. A yellow-gold link beside a silver one shows the same surroundings twice — once with the blue end subtracted and once without — so the pair carries a built-in warm-cool contrast that no single metal has. Where the metals are a similar lightness, the hue difference is what you notice; where one is polished and the other matte, the gloss difference can dominate instead.
How it ages: Each metal ages on its own schedule: silver tarnishes, brass and copper patinate, rhodium plating wears, and gold changes little. Over time a two-tone piece can drift apart in colour unless each part is cared for.