An audio component you just can't let go

I have a few pieces in my system that qualify, except (as you specify in your post), I haven’t replaced them or removed them from my system.  Occasionally I take them in to have some of the internals upgraded or repaired, but they will always be an integral part of my system. 

So the pieces I can’t let go of are my musical instruments.  My string bass, my electric bass (which turned 50 two years ago), and a couple of my guitars.  I haven’t played them in over 35 years, but they were so prominent in my life that I’ll never sell them.

 If we speak of electronic component, my akg k340 and my Sansui amplifier  of the alpha series are irreplaceable in term of S.Q. /price ratio ...

VTL pre and power amps.

My SAE 5000 Impulse Noise Reduction System. It is not used now but when I get the rest of my 70s stuff hooked up it will be.

Sony Tc-K7II cassette

Pioneer SX-1050 receiver

Pioneer PL-630 turntable

Teac A-2300S open reel

JBL L222 Disco speakers