I have been lucky with my purchases over the years, and have not really had a serious dud except for one.
I have kept a lot of my gear long, and much of it has given good service for decades. My three main turntables are well over half a century old. I have got rid of very little.
When we went on the Giga zone at Benedict Lake, I needed to update the router. I had previously used Linksys routers with good results.
So I bought a Linksys WRT 1900 AC. That was an absolute piece of junk. It needed rebooting often multiple times daily, especially if there was heavy traffic. It was also an expensive router. It improved after wiping out the software, flashing the BIOS and installing open source Tomato software. It still needed periodic reboots, especially when the grandchildren visited and were on their mobile devices. In the end I gave it the deep six and went with Netgear Orbi. I have since also put that in our new home, and have noting but the utmost praise for the system.
A relatively sorry purchase, was my first AV pre/pro which was a Rotel. It did not have HDMI, but no pre/pros had HDMI back in 2005, so that meant workarounds with a switch. The unit was unusually susceptible to RF interference. I did not have it long. It sold well. Then I bought my first Marantz pre/pro, and still have it, but it is in storage. The Marantz pre/pros I had at the Lake and at our Eagan town home are still in use and giving good service, they are the same models. With the new studio I put in the Marantz 7705, that I am very pleased with.
I try hard to avoid disasters, keep my equipment for long periods of time and take care of them. I mainly update for reasons of obsolescence. That involves mainly the pre/pros and TVs. I rebuilt my HTPC for 4K, and updated my DAW with a new build once.
In the AV era I have used pre/pros and external amps exclusively. In the audio only era I used separate pre amps and power amps. My power amps have been exclusively from Quad manufactured by the Acoustical Manufacturing company Huntingdon UK. I have to say that approach has served me very well. All my speakers, have been my designs and builds. That has been another really good decision. This has allowed me to enjoy good sound at comparatively modest cost for 67 years. For me longevity of equipment is a very high priority. I think I have by and large been successful in giving junk a very wide berth indeed. That is a key factor in keeping costs within bounds.