If you embark on an Engineering career, whether certificated and University-qualified, or apprentice-trained and college-qualified; or even if your choice is to get your hands dirty as a technician, or junior or senior Engineer; the first thing you learn is that the single most important word in your vocabulary is, Maintenance!
I spent seven/eight years at sea, looking after the electrical systems on ships large and small, and the voice I recall the best was that of the Second Engineer whose mantra was, ‘You walk around the entire engine room for one purpose, and one purpose only; to detect the oddity, the anomaly.’ He explained, ‘If you walk around the main engine steam turbine casing, you simply run your hands over the casing as you walk by, if you pass a pump motor, a gear-box, you touch it, if you enter the boiler room area, you casually flick open the sight ports, and check that the flames are bright: then you know that you are absorbing information as to the healthy state of that turbine, or pump, or boiler. As well as your eyes and your hands, keep your ears trained to pick up the unusual, the click, the knock, the whine, the unusual clatter. If a casing is too hot, there might be a shaft bearing concealed within, and that bearing is short on lubrication, you have done your job, because you have detected something which may go wrong within a very short space of time’.
Now the reader must realise that sensor technology has taken a great deal of work out of the hands of technicians, and placed it within the purview of computers, which can check an undue rise in temperature, or pressure, a far sight faster than any human could detect, and flag an alarm, or sound a siren; to draw the attention of the technician engineer to that particular problem, whether on a main engine, or a pump; or wherever. But the unfortunate trend within ships, within automation wherever it serves, is that the human beings are and have been phased out, with computers allegedly doing their jobs; because human beings actually cost a lot of money. So the bean-counters have built ships which rely upon technology to do the jobs which technicians and engineers performed for decades, with a huge discount in the numbers of men who serve the giants held within the engine room spaces.
An Arleigh-Burke class US Navy destroyer carries a complement, men and women, numbering some 280. Some tend the guns, torpedoes and missiles, others work and maintain navigation duties and the vast electronics systems which are the very heart of modern-day weaponry and nav. systems; and many more tend the engine turbines and other gear which gives the destroyer its speed and manoeuvrability.

A Littoral Combat ship is, admittedly, a smaller ship than a destroyer, but it only carries a crew of fifty, as most of the maintenance work is supposed to be carried out on a shore-party-based system; meaning that this type of vessel does not carry anywhere near as many technician/engineers as similar US Navy ships. But, the question must be asked, if Arleigh-Burke destroyers have performed, mechanically; almost flawlessly for over twenty years, how come the USS Fort Worth tried to set sail with no lube oil in the precision-made gear boxes, and everything burned up?