Do you buy gear new, used, both?

Iʻve always tended to go with value.  I want the most sound for my limited audio buck.  I bought my tube preamp and DAC new.  I play all of my digital stuff off of a Linux based miniPC I recently built from new hardware.  My loudspeakers came with a new active crossover when I got them.  But my 12 channel power amp (I use 8 channels) is one I picked up used for all of $500.

The last time I bought a new turntable, Jimmy Carter was president.  I ran a Linn LP12 I picked up used in 1987 and ran that for 30 years.  My tables since have always been used.  

I ran a Revox A77 deck for 40  years that I originally bought used.  But the Nak cassette deck I had was one I bought new.

I recently bought a well-made DIY set of the SEAS Thor loudspeakers.  Got one HELL of a deal on that!  The kit, new from Madisound, is something like $2700, and thatʻs before you spend the money and effort to make the enclosures.  The seller was a cabinet maker who did a great job on them.  My cost was $1200 shipped to me.  Not bad.

Mostly new here, but I have  bought used occasionally. 

Mostly new, although some of it quite old now.

My last big purchase, a turntable was second hand, although I did buy some new bits for it.

I keep my equipment for years.  So depends on the type of component (amplifier, preamp, DAC, etc). Generally, I would buy used where there are no moving parts, age (less than x years), condition is an 8 or better vs price (discount from new if current model). For items with moving parts (CD players, turntables, etc.) generally no, but have done so on a CD transport and a phono cartridge where I knew the seller.

For open-box (new or returns) - condition, seller (store or individual) and discount from new selling price would be determining factors for me.

Almost everything I own is used. My new components are a roon nucleus and a Sonos Port