Long-Life Electronics
The life of your electronics will probably be more a function of your design
then it will be of the components. You can review the component reliability data
from the manufacturer's websites. Without a proper design you will not achieve
the specified reliability. Without process controls in manufacturing you will
not be able to manufacture a reliable product. A strategy of trying to test the quality into a product is doomed to failure.

A lot of components will follow the Arrhenius activiation law which estimates
the component life based on the operating temperature and the maximum operating
temperature specification of the component. Reducing the operating temperature will have a dramatic affect
on life. For example -- reducing the operating temperature of  electrolytic capacitors 
by 10degC will increase the capacitor life by roughly a factor of 2. 
A 105degC rated capacitor run at 85degC will last roughly 4 times as long as
running an 85degC rated capacitor at 85degC.

You can switch high amounts of power with MOSFETs and IGBTs. For reliability heat
will be your enemy. You want to transition the semiconductor from off to on and on to off quickly
to minimize the heating. There are transient thermal curves at the back of the datasheet.
The thermal mass of the die is small. Switching the transistor in 10uS versus 1mS will have a dramatic affect on the junction temperature.

In general -- 


Design review -- thermal, electrical stress, environmental stress
Design qualification
Choose components with a wide temperature.
Choose quality component manufacturers. 
Handle your components properly -- ESD, humidity, environment