It's just that when a part fails and you replace it with the same part you have effectively thrown away that amount of money with absolutely nothing to show for it because the best you can hope for is to have the exact same functionality as just before the failure. And believe me, to replace stock parts with stock parts on a used ender 2 is most definitely somewhere in between throwing away your money and pissing in the wind. If we take these part failures as a chance to upgrade then at least we can enjoy a better texture or reduced salmon skin on the surface of our prints for the money and time we just spent repairing the failure. It is just a thing to understand what is an upgrade, and what is not.