Stars can last for billions of years, but like anything that's burning, they will all eventually run out of fuel. A fuel-depleted star will collapse and become a white dwarf star, but that's not its ultimate fate. SciShow explains what is happening inside when a star burns out and eventually collapses.
In fact, a star goes through quite a few phases during its existence. So where are all these old frozen stars? There are plenty of them, just nowhere near our solar system. What's really amazing is that our scientists have learned about them at all and can figure out what happened at the atomic level. -via Damn Interesting