The simple answer is yes if you want to keep it running.
Ask yourself: do watches, power tools and motorcycles eventually need to be overhauled and/or restored? The answer, of course, is yes and this applies to everything built by human hands.
I don’t need more overhaul work and many people are prepared to throw old things away when they fail, but when this is rare and collectible hi-fi gear, that may not be the best idea. I overhauled my Toyota Prado starter motor last year for example, it’s a Japanese Nippon Denso starter, and that’s what I want on my vehicle. I could have bought a cheap new one, it would probably last only a year or two.
Older hi-fi gear is generally reliable and lasts a lot longer than newer gear. However, there is no escaping the fact that eventually, someone HAS to spend money to have it overhauled or restored. That should preferably be done before it fails, taking out speakers, output devices, catching fire etc. Parts get hot, change, wear out and eventually fail, even in the most expensive equipment. If you love a piece of equipment, consider giving it some TLC before it fails.