How long do you or should you keep your gear.

Still have a Sansui 7070 that was purchased in 1977. Still works and runs 12 hours a day in my wife's salon. Still using my pioneer pl112D turntable that I received for Christmas from mom and dad in 1974. 

I've had my Quicksilver Mid Monos since 2015 and while they are being replaced, I have no intention of selling them.  Same thing for my cj Classic 2se, it served me well since 2014 and I just replaced it with a Zesto Leto.   I can say will certainty it will be the heart of my system for a while, its that good.    

I've had my Magnum Dynalab MD 102 for about 10 years, no intention of selling ....

DACs ?   Disc spinners? They come and go a little more often, I almost view anything that spins a disc as a consumable.  They die, get out dated.

DACs can be viable for a while  but are forced into obsolescence  by new codes etc...  I spend up to the point of diminishing returns , relative to the rest of my system on those.

@larry5729

i have repeatedly heard Magico speakers that sounded terrible. The speakers are spectacular in their ability to accurately articulate the input. The problem, especially with Boulder is incredibly accurate (like Mark Levinson) … studio monitor stuff, incredibly revealing, but without soul. Speakers and electronics that are peerless in accuracy, but lose the music. On the other end of the spectrum my system (see my ID)… Audio Research / Sonus Faber / Transperant.

So, Magico is unassailable in reproducing their input. Incredibly well engineered. 

@oddiofyl I enjoyed my Quicksilver Monos for years. Tone to die for. After maybe a decade or so, though (through which I lived through stretches of good times and times of finicky tubes and various preamp meltdowns & misadventures), I took a flyer and bought a Primaluna Integrated. Maybe it's because, in the interim, I wanted to simplify my audiophile life and concentrate more on getting better on my musical instruments, but I honestly don't look back.

I've actually had good luck with tubes...QS has been super reliable.   I'm actually going to put the CJ pre and QS monos in a second system.

I auditioned my last two sets of speakers on PL integrated amps and thought they sounded quite good.