How long do most planets last?

Planets form from microscopic dust grains around young stars and eventually face destruction, but their lifespans vary dramatically based on their host stars. Earth will last about 9.5 billion years before the sun expands into a red giant and destroys it, but most planets orbit red dwarf stars that burn fuel much slower and can sustain planetary systems for trillions of years. These longer-lived planets typically die from internal processes like losing geological activity rather than stellar death, with rocky planets around red dwarfs maintaining habitable conditions for 16-90 billion years before their geology shuts down.