My very first computer was a prebuilt by a major company. After a year or so, I began to have problems so I took it in to a local computer store. They diagnosed a failing PSU so I had them order one as it was proprietary. Two months and no PSU. They could no longer get the required one for it so it was a brick (BTW, this was in the early-mid 90s). This time I bought one from a local company that did builds and repairs and they had one built and ready in a few hours. At that point I took a detailed course on building a computer. I'd open up the one I had, studied it, and realized it was pretty simple to assemble. The next desktop I built myself and since then have built every desktop. Not only do I insure it's repairable but I like researching parts and having control over what goes in the system. No Cheap Parts!