Do you buy gear new, used, both?

Both.  New when I was flush, used when my budget shrank.

Also, always new for electromechanical items like speakers, cartridges, turntables, and optical disc players.

Used more for electronics.  Never buy new for AV pre/pros where fast technology makes instant obsolescence.

I only buy NEW. There may be some situation in the future I would buy used but nothing so far!

@fthompson251 Used Cables are the one item I am the most nervous to buy used because there are so many counterfeits on the market. I don't think I would have a problem buying them from a company though such as TMR or The Cable Company. Some of those clones look exactly the same to me and I would be afraid to buy them from an unknown individual unless I knew them.

I buy new gear. I keep it for a long time say 7 to 12 years on average. I do in depth research. Depending when in my life... early including travel to listen, audition. Now, after fifty years, in general, I can read reviews and know exactly what it is going to sound like. I have now often enough heard about a combination of components, thought through what they should sound like, and then listened to them and found them to sound exactly like I imagined to trust my experience. 

So, new from a dealer. When I am purchasing something that can cost as much as a car... I don’t want any unsettling doubt involved in the process. When I was young, I remember the joy of purchasing something at half price, angst of wondering if it was going to be functional and what I expected and then the horror of realizing it had some flaw. 

I used to scour the thrift stores for stuff when I was younger. (back when I was the worlds poorest audiophile,probably still am🤑) Now that I have somewhat of an understanding of system building. I find that it is much easier to build if you stick with buying new. Trying to search for a specific product in a jumble of shelves at goodwill is not my thing.