I've no idea what the rated lifespan of the LEDs used in the DS screens is (it's probably different from model to model as Nintendo have used various panels from different manufacturers), but they are in the order of tens of thousands of hours (and they are considered to have reached the "end" of their lifespan when their brightness is down to 50% of what it was new). So yes, if you play your DS a lot, you may well notice some dimming over the course of a few years. White LEDs have better lifespans than the CFL lamps used in many larger LCD screens (not to mention a fraction of the power consumption - remember the Sega Game Gear and Atari Lynx, which would suck six AA batteries dry in three hours?).
Although this is true, they don't gradually grow dimmer, they more or less just go all out downhill towards the end, as is usual with most LEDs (Have nothing to do with how lightbulbs work rly for the most part)
In any case, the life-expetency of TFT LCDs overall is supposedly very long. I can tell you that I have had my DS Phat for 3~4 years now (Day it came out, broke a month or so back) and I never noticed any progressive dimming in the backlights)
I've had my current DS Lite for a year and the same can be said, used every day, usually for 4~15 hours a day. They're expected to last 'millions of touches' and I've probably hit at least 1m touches already. :/
@Sicklyboy decent soundbars do give *some* surround effect but this isn't surround and it doesn't try to be, so it's nothing more than ordinary stereo speakers put into a plank form factor which is bigger than separate speakers would be and not any more convenient since it's only stereo anyway. and you pay extra for the oversized case with nothing inside it
@The Real Jdbye, sure, my AKG headphones give a bit of a surround effect too because they've got a great fucking sound stage despite being stereo by nature lmao. But yes that's my point exactly. The only benefit to a sound bar is they generally "just work" (except for when they don't)