The modern smaller lightweight chargers that use a switching power-supply usually do not last anywhere near as long as the old simple transformer ones that weigh a lot more. Now-days with the price of copper gone through the roof, it is hard to find anyone who still makes a simple transformer based one that uses a lot of copper in the big type transformer. It is hard to stay in business if you are producing a transformer based product that cost a lot more than the competitors switcher that has the same output current rating and cost a lot less.
The trouble with switchers having a short life expectancy is probably mostly due to the solid-state device having to work with the higher line voltage, and also that the bean counters will always use the lowest cost components. A solid state device that can handle the high voltage spikes seldom seen on the incoming AC power line cost more, so most manufacturers use the lower cost components that work fine until a voltage spike that more expensive components with higher voltage ratings could handle without being damaged comes along and blows out the lower cost component the bean counters opted to use to save a few dimes and then the device no longer works, and the consumer has to go buy another one.
So if you want to give a charger designed around a switching power supply a decent chance at a long life, protect it from voltage spikes on the incoming AC line by using a good surge suppressor on the line feeding it, and along with that do not leave it connected to the AC power when there may be a lightning storm coming through the area. It only takes one brief electric spike to wipe them out.
