I don't see why electronics of any kind should just fail in 8 to 10 years. If you looked around your house, you would probably find some electronics which has been there a long time. My favorite AM-FM radio is roughly 30 years old.

The bathtub curve is the usual way of looking at electronics failures, which suggests that many failures are in the first few months, then it drops off to a low flat rate, then gradually starts to increase later. The graph below suggests that failures increase around 25 years. Moreover, welders are generally not powered on, which should extend their life, versus something plugged in 24/7.

http://doi.ieeecomputersociety.org/c...res/d20881.gif

I have a Thermal Arc inverter welder which is probably 20 years old, it works. I was visiting a shop last night with a PowCon AC/DC, still in use, I would guess 20 years.

Richard