A black hole naturally lasts for billions and billions of year—many more years than the current age of the universe. The reason is that the only way a black hole can die is through a form of "evaporation," which occurs particle by particle; this is an unimaginably slow process.
This form of evaporation was discovered by physicist Stephen Hawking and is called Hawking Radiation. Black holes have an event horizon, which is the area that determines whether or not an object will stay where it is or be sucked into the black hole. If the object is inside the event horizon, it will inevitably fall into the black hole. If it is outside the event horizon, it may remain where it is.
Quantum physics theorizes that a particle and its antiparticle can spontaneously appear. When these two particles meet, they destroy each other, usually over a very brief period of time. Hawking determined that if a couple of particle pairs were to be created near the event horizon of a black hole, there is a chance that the particle of one pair and the antiparticle of the other could escape and interact with each other, while their opposites would be sucked into the black hole. This interaction would create energy, which would have to be deducted from the black hole as mass because energy cannot be created. This would have to occur many times over thousands of billions of years until the black hole simply runs out of mass and fades away.