How many people here generally buy used?

My standard practice for years has been to shop for Class A-rated components (Stereophile) of five to 10 years prior. Can get them for great prices, enjoy what was recently state of the art sound for a whole lot less money.

I've bought Audio Research, Ayre Acoustic and other brands/models this way with GREAT results.

I started doing this in the '70s through the old paper-printed Audiomart classified publication. But now, with the Internet, it's way easier.

Back in early days, lots of brick and mortar audio retailers, purchased more new or demo. Now days, nearly all used, buying new without the ability to hear in my system changes the new versus used equation in favor of used.
Also, I tend to modify my equipment over time, I violate warranty buying new. Bypassing break in is nice as well.

I still occasionally purchase new when I have a specific piece of equipment in mind that never comes up for sale used, or when it does has minimal discount over new. Has to be at least 25% discount over new for me to even consider it.

I kinda fell in love with the Rotel 900 series decades ago. Liked the looks and availability on ebay. Only new piece is the 965 LE cd player because of moving parts for $600. I know this is pretty low rez compared to what you guys have but I couldn't even afford this at msrp. So under $1000 for almost $4000. It took much patience. Also got my "dream speakers"-mint B&W matrix 3, for $400 cash at a local store.

Most of my equipment is used, but lightly so. My Sonance amp and Rotel preamp are used and both from the early 90s. But both are so clean externally and internally, as well as sound, as to be like new in operation. Together, they cost $200. My Marantz 6500 series Tuner and SACD/CD player are 1994 and are also in appearance and performance as new-both for $110. My Yamaha sub and Cambridge sound works mini monitors are used and together cost me $80 through Craigslist. Both the amp, tuner, Cd player and speakers were bought locally and carefully. The preamp was mail ordered through ebay, again as carefully as one can. My self-moded Audio Technica tt and cartridge (At750) were bought new, and replaced my Philips Electronic (the speed was deteriorating and though these parts can be had on the internet, I really didn’t want to deal with that) and at440 cartridge. The local Wax Records, which sells some new and used equipment, took my turntable in trade towards a new one. It’s obvious that these days the used market is a difficult one because the home-grown audio shops of the past are gone (though the newly burgeoning record shops are carrying some used equipment), thus it takes more time and attention to detail to buy used now. All of it was an evolution as particular items either wore out or seemed wrong. Frankly, I can’t afford to buy what I would like New, but the process of understanding what to buy used, is not only fun but hugely rewarding.

Both. Used when ever possible. but some times, new technology and outstanding products are not available used (for years).
KNOWLEDGE + PATIENCE+ OPPORTUNITY + FAST ACTION = VALUE. Have bought  both new and used with this formula and sold from 1 month to 30 years later and recovered between 55% and 115% of what it cost. IE. bought new speakers for $7500, sold in 5.5 years for $7000; 
amp/preamp new at $800 & sold 15 years later at $700; other speakers new at $1,000 sold 30 years later at $800. 
All current system components both new and  used cost 62% of their retail price. Only the preamp and speakers were bought new... used just do not exist (yet). The pre was significantly discounted because it was a discontinued model, but still, no used to be found. 

If you select (target) wisely, sometimes you also just get lucky. I have found some sellers care very little about getting top dollar  or “what it is really worth if you have patience in finding a buyer who really wants it”...they just want it gone... fast... no hassles. Getting a great deal on great equipment is like finding a fantastic bottle of wine at an unbelievably low cost. It’s SO enjoyable!