How long does a white dwarf stage last?

A white dwarf stage typically lasts for billions of years, as these stellar remnants gradually cool and fade over time. They do not undergo nuclear fusion, so their energy comes from residual heat. Eventually, they may become cold and dark, transitioning into a "black dwarf," although the universe is not old enough for any black dwarfs to exist yet. The time a white dwarf remains visible can vary depending on its mass and initial conditions.