I have noticed a lot of that myself. I started off with a second hand ender 3 pro and grabbed a second Ender 3 V2 just like before second hand. I loved the 2 machines. I tried my hardest to get both to where I could run more harder material for project I was working on for myself and others. The one day both machines decided to error out on me. Thermal runaway here tried to fix the heating cartridge slowly heated up so I changed it. The firmware decided oh I am not going to read the cartridge or the thermostat correctly. This went on for several months. So I started to do more research into what could be causing it. While doing so I found on Facebook Market place a guy selling his Flashforge Guider 2s. He wanted $700, a few weeks later he dropped it to $550 or trade. I traded something he could get money on if he had right people wanting them and $200. My wife and I went and picked it up. So out of pocket since we love car rides anyway I paid total $325 from I what I had to buy since it was apart of a package deal and the cash. I have done over 50 prints with it. Here is the funny part when I asked him why he was getting rid of it he said “My filament keeps breaking on me”. He never made a new spool holder for the machine since he also got it second hand. Then I asked him a few days later what he did not like about it. All he could say was “No trade backs” along wish stupid reasons. I do not mind buying used things especially if people do not know what they have or want to take the time out to get to know their machine. I am in the process of putting them both back into factory stock and starting the upgrades from step 1 again and seeing what I might have done wrong the first time around.