Because in many cases the equipment will have been damaged or otherwise compromised, creating headaches for the next person.
This is a shame but it’s really just a reflection of what many working in technical fields know well – that the best equipment is unmolested equipment, in original condition, ready for someone to work on it who really knows how to care for it.
Don’t get me wrong, I’m not saying that equipment shouldn’t be worked on, only that it just has to be worked on by the right people and sadly, they are few and far between. Most attempts at maintenance introduce faults like damaged printed circuit boards, compromised wiring and low-quality parts.
Undoing much of this can be very time-consuming and tedious. It’s actually not part of my job description, nor is it something I enjoy. Thankfully, as the owner of my business, I can choose what I work on.