Excerpts from
http://www.gripe2ed.com/scoop/story/2008/2/28/1371/09249
I've been a TV servicer for 35 years and an independent factory
authorized servicer for most of that time. In the past, my profession
never recommended extended warranties, since they would typically cost
more than one or two repairs.
There was a change that took place around 2000-02. The manufacturers
responded to pressure from dealers and customers, and redesigned TVs
to be home repairable by exchanging circuit boards. The problem is
that no one builds new boards for old sets, and when they run out
(18-24 months) the TV becomes unrepairable.
The lifespan of TVs used to be about fifteen years, but that is no
longer the case. Most servicers feel that the lifespan of the newer
models will be about five years, and that any repair after about two
years will result in replacement rather than repair.
Based on the past history of the following failure modes, servicers
feel that there will be a severely limited lifespan of new TVs: