Generally the GPU and rest of the laptop will last longer than the usefulness of the laptop itself. I have an 8 yr old Sony which I used for moderate gaming at the time, it got seriously hot when gaming but never showed any problems. It's still works perfectly apart from a battery that doesn't hold a charge anymore. It's so old though I no longer use it.
But like any PC component there is an element of luck. If your very unlucky a component can die within days of getting it