LCD screens don’t really wear out. The lifespan of the device itself depends on how often you use it, and what electrical source you plug it into. If you unplug your laptop and then plug it back in after a few hours, that’s like using it for 20 years without turning off the screen! (The reasoning behind that is that, while we typically think our devices need time to “power down,” they actually spend most of their time powered up–and all the while drawing power from an electrical source or battery).
RAM does not get burned out like certain other electronic components such as semiconductors. It simply starts slowing down over time (in biological terms, this would be called “senescence.