Why the cartridge outlives the finish

A mixer tap is a brass shell wrapped around a cartridge. The shell is what you pay for visually. The cartridge is what decides whether the tap is still pleasant to use after ten thousand mornings.

We use a 35 mm Kerox cartridge, tested to 500,000 open and close cycles. At six uses a day that is well past two hundred years, which is obviously not the point. The point is that the failure mode of a cheap cartridge is not a leak, it is a gradual sponginess in the lever, and nobody replaces a tap for sponginess. They just live with it.

It is also why we sell the cartridge on its own. If a tap ever does go, it is a fifteen minute job and a $40 part, not a new tap and a tiler.