I’ve bought all my gear used, except for DACs where I buy a new one every four years or so ($1 - $2k budget). Appreciate this may not be quite the same as “refurbished”
For McIntosh, I always work with the folks at Audio Classics, and for other things scan larger dealers to find what I am looking for that they may have from demo, etc. (I put together a nice 2nd rig this way)
Works for me
Good luck!
Have a great day