LCD / LED life time is 60,000 hours. but depends of Brand / maker .
Samsung / LG / Sony / Panasonic / Toshiba / Sharp / Philips usually reached 60,000 hours or a little more,
those buyer brand / local house brand / China Brand , usually will not reach up to 60,000 hours , some only 40,000 hours .
Old Plasma models before 2007 is less than 40,000 hours.
New Plasma after 2008 models by Panasonic / Samsung / LG / Pioneer also New Sanyo 2010 models is 60,000 hours. new 2008 Plasma technology with out burn in / over heat issue ,lower power consumption.
Panasonic / Samsung / LG / Pioneer 2008 onward Plasma life time no difference with LCD / LED TV. and lasts longer than low price LCD TV for sure.