Spades vs. Banana plugs ??

Not my experience at all. My high end connectors on Scanspeak drivers and Bryston amplifiers all come loose with spades or bare wire, on their own, without mortal assistance. Poltergeist?

Of course, when loosing is a serious problem, lock washers are invariably used.

On the amp end I have ended up with bananas and spades, because I regularly swap amps and have to. These are gold plated copper bases with threaded ends so that I can easily change between banana and spade tips. I feel a bit safer when using the bananas (for reasons well covered already).

At the speaker end I use solid copper bananas. I made them up with twin screw ones, but threw one screw away and filed that hole with solder. My understanding is that keeping air away from copper connections (or silver) with solder, gold, or rhodium reduces oxidation/tarnishing.

However, I have never tried to hear the difference between plugs or bare wires in a system where all else is equal, so the above is only based on reading, not listening.

Bare wire at the amp end; I test the compression regularly. Bananas at the speaker end, strictly for convenience as I swap speakers, and I don't have much faith in switchers.

My tarantulas prefer bananas

I just recently switched speaker cables and started using Audio Art’s top of the line. Of all the bells and whistles, they have locking banana plugs.  So far, I’m thinking this is the way to go.