Why do electronics actually need to be serviced?

Because all electronic devices, even those designed for the international space station, for example, contain parts that change, wear, need cleaning and adjustment over time.

When you add in mechanical systems like levers, switches, belts, pulleys and connectors, as found in many types of hi-fi gear, you have a combination of parts and systems that will wear and need periodic attention and maintenance, over time. Proper maintenance will prevent premature failure, improve performance and reliability and therefore your enjoyment of your equipment.

It’s a strange quirk of human nature that we sometimes purchase things and expect that they will just keep on running without any attention. This is not true even of a kettle with almost no moving parts. It’s certainly not true in the case of a turntable or even an amplifier. Mechanical linkages and drives need cleaning and lubrication and this is fairly easily understood. But electronic parts also change over time, most notably electrolytic capacitors, some semiconductors and resistors.

It requires a really careful eye and lots of experience to know where to look, what to look for and how to correctly service each of these types of electronic and mechanical parts and systems. One thing is for certain, your hi-fi equipment will need money spent on maintenance if it is to keep running reliably.