The original PSVita uses an OLED display, this technology utilizes organic components which degrade over time. OLED displays currently on the market have an expected lifespan of 50,000 hours of use - that's over 13 years of use 10 hours a day. Of course that's just a figure - it doesn't mean that the display will just stop working, it means that it gradually loses the "brilliance" OLED's are known for. Think about all the old LCD consoles like the Game Boy or the Gamegear - those used very primitive technology and yet they're still functional today, albeit often suffer from contrast issues, ghosting or burn-in. I wouldn't worry about your PSVita decomposing all of a sudden - it won't always look like brand new, but it also won't spontaneously combust for no reason.