Do you buy gear new, used, both?

I go both ways.

(Insert humorous response here)

Due to available finances, I can only acquire components of a certain quality if I buy used. Luckily, there usually are a lot of options on the used market and I am always willing to wait for the right deal.

That being said, I do occasionally buy new, such as recently purchasing a Denafrips Iris DDC, but this is rare.

My primary system is mostly used except for the turntable, cartridge and all the cables. The HT 7.1.1 system is mostly new except for the subwoofer, center channel and front speakers. The third system is all new (old repurposed receiver, old CD player, old turntable with a new cartridge, and new KEF speakers). 

The primary system is mostly higher end stuff. The only way to justify purchasing it was with deep used, or demo discounts.

Both, but will go used if I find exactly what I'm looking for happens to be on the market.

Mainly new, a little used (tape deck), plus some DIY (wood cabinets, leveling platform, cable Y-sleeves).

Both here.  Demo gear is my favorite.