Speaking of works of art and engineering, the three HP Voyager series calculators on my desk (12C, 15C, 16C) still work as well as they did several decades ago when they were new. As does the other 15C that I regularly carry around and occasionally drop.

My father only had a problem with the battery leaking in a bigger HP calculator that had these expansion modules. His 15c is also still working since the 80s.