I bought a GTX 750 TI in 2014 which has never missed a beat since.
My next 2nd hand buy was a complete PC (without a graphics card). I replaced the sh*tty case and stock cooler then put in an SSD. Everything went well until the POS cheapo PSU went up in flames (not literally). I replaced that in a month's time and everything has been great again ever since!
Edit: I'll probably never buy 2nd hand again, since the upgrades will probably go over my 2nd-hand-price comfort level.
Yes, many times and for many friends. We always go to Universe Direct in Montague Gardens. They sell refurbished Dell, Lenovo and HP machines with Windows 10 on it.
The Dell machines are superb. I worked out I have, for myself and friends (and a Computer Club I belong to) purchase 30 machines, both desktop and laptop, in the past 4 years. Not one has given any trouble