Both.
I used to buy items new, but that was when I first began buying High End components, circa 1985. Twenty years later, I bought a used speaker system (Hales Revelation IIIs), and have often bought used components, although some things I will only buy new.
I had the unfortunate experience of buying a preamp from Upscale Audio in 2009, a Convergent Audio Technology SL-1, which I’d owned in 1988, so I knew what it sounded like. The unit I got from Upscale sounded nothing like the Convergent I’d bought new in 1988, and getting Upscale to take it back got unpleasant. They actually refused to take it back, although the credit card company reminded them I’d met their conditions and had even called them back within 45 minutes of installing the preamplifier, when I realized upon first listen, that something was wrong.
Eventually I shipped it to Ken Stevens, who found someone (clearly, a previous owner) had changed a resistor in the power supply, altering the sound for the (MUCH) worse. I ended up going to Rush, New York where Ken is, and buying a Convergent preamp directly from Ken, so that worked out well; I didn’t have to worry about the sonics. To this day I don’t know if Upscale ever got that preamp back.
I did buy something else from Upscale, 10 years later, and was put on hold. Kevin Deal came on the line and reminded me I owed them a preamp from 10 years ago, and I calmly told him it was defective - as I had told them - and that Ken Stevens now had it, that he had found someone had monkeyed around with the preamp, and they could now get it from him. (I never found out if they did or not. Wasn’t my concern any longer.)
So now, I test electronics immediately when I get them used, even from a dealer. Otherwise, I’m comfortable (mostly) with used components
