Safety of Older Electronics

Some electronics never die. They just get moved to secondary, tertiary, etc. systems. In my case, I have two old receivers connected to televisions. I'm guessing one is 25 and the other 30 years old. The remote sensors are on all the time and occasionally one forgets to turn the receivers off. They can be replaced with relatively inexpensive amplifiers for how they're used, but I thought if it ain't broke don't fix it. At least until recently when I've started to wonder if continuing to use them is a smart idea even though there is nothing apparently wrong with them. I'm thinking in terms of a damaging (catastrophic?) failure particularly when the receiver is unattended. I'd appreciate input whether one should continue to use older equipment that can be inexpensively replaced.
I am running a Pioneer SX 737 receiver (circa 1976) while in temp housing and I leave it on all the time. I need to install the replacement relay so that I can turn it off and on without banging and clanging but I am not worried about it electrically. It is plugged into a PS Audio Premier Power Plant so I trust it will be shut down if the sparks start to fly. If I have enough advance notice I'll be sure to invite ya'll over for the weeny roast.
Had a Sherwood receiver (1972). Thought everything was ok with it till I left it on one morning when I went to sleep after my night shift at work. The unit went into some weird oscillation mode emitting what I would consider some sort of damaging sine waves. It took out the woofers in my vintage Advent speakers. Literally twisting the voice coils in their gaps, totally destroying them. Its a good idea to have a receiver like this refurbished with critical caps and resistors replaced not to mention a complete inspection of the innards. There is a gentleman down in Texas who does this sort of work. Can't remember his name but I think his company is called Circle Audio, I think.
One thing that can fail are electrolytic caps.

Have them repleced and all should be good. It will probably sound better afterwards.

You might find the odd high power resistor fails also.

Every thing else should be fine.

A good tech should be able to assist for a reasonable price.