I would keep the original brass and try to find solid, unlacquered brass to match or complement it. You can filter for unlacquered brass on build.com or similar and I’d also look on house of antique hardware.

You can let the brass patina naturally or age it in less than an hour by suspending it (or putting it on like a wire rack) in a container with some ammonia. It’s pretty easy and since it’s unlacquered brass, if you go too far you can always polish it and start again.

It really depends on the style you’re going for in your house though. The quality of the hardware and the finish matters as much as the color tone imo. Anything can look bad if it’s cheap paint and plastic coating. I also have no problem with mixing finishes if they’re all nice. And some people prioritize ergonomics to replace knobs with levers etc which is perfectly valid.

If your house had out-dated polished builder's grade brass fixtures (door knobs, hinges, etc.) on the 1st floor and unique (but damaged) original brass fixtures on the 2nd floor, would you take the opportunity to re-do all fixtures during a home addition renovation?

We're adding on to the back of the house, and our builder's standard package includes black matte fixtures, which wouldn't match with either. To be honest, I think black matte is a trend and too industrial for my tastes. But I don't love the polished brass look either (although I'd argue that's a little more timeless than black matte, maybe?) I'm torn -- my house is very mis-matchy already. We have shiny chrome in all our bathrooms, and stainless steel appliances (sink faucet, stove, fridge) in our kitchen. Should I surrender to having a totally mismatched house or should I try to bring order to this? How would you handle?