My oldest still working monitor is a 15" Compaq TFT which is now 14 years old. Actually all TFT monitors I bought are still working. They seem to outlive my computers by a factor two to three.

With CRT monitors I had less luck. My first one had a print board failure within three years and pixel sharpness of the others deteriorated significantly after a few years. Even my NEC MultiSync CRT which was regarded a high end monitor at that time didn't live longer than about 5 years.

On the other hand my TFT monitors give still the same picture quality as when I bought them (all high res monitors use DVI and HDMI which is less prone to signal distortion due to aging electronics than VGA) and only one has a single broken pixel.

I can never ever recollect having any problems with monitors. Ditto with olden day CRT TV sets. Most simply were overtaken by newer developments

In any form of electronics, if something is prone to fail, it will likely happen within the first few weeks of operation.

Thereafter the two biggest killers of electronic devices are a) power surges, turning on/off - and b) the weakest component of all, which is subject to aging - "capacitors". What killed the old incandescent light bulbs, even the newer compact fluorescent ones is the turning on/off.

Transistors [including those embedded within integrated circuits] generally only fail when subject to current flows well outside their specs. Technically solid state devices have a nominal life well in excess of our own.

Modern devices I often get handed to try and repair usually fall into three categories:

1. User abuse.
2. Cheap consumer devices where connecting wiring, for example, simply isn't up to the job.
3. Both of those together.

Unfortunately what permanently kills a good device is the progressive failure of one component, leading to the successive catastrophic failure of other components in the chain.

I belong to a long time forum where we restore/refurbish olden day valve/tube radio receivers and transmitters. I have radios as old, if not older than myself and I'm 74.

No! We don't "smoke test" old equipment which falls into our hands. We leave that to idiots and Audiofools.

I just had a 10 year old 19inch DELL LCD die out....it was the LCD ballast, this is the 1st LCD i've ever had go bad.