Because this is where they make much of their profit. Besides, they have to pay for the running costs of keeping a shop (Techs, tools, software, documentation, certifications, electricity, rent and so on...). They also have more responsibility if something happens during/after the repair is done. I could easily repair a laptop using parts of ebay very cheap, but running a company is a entirely different thing. For instance, having parts in stock is bloody expensive. Sounds mad, right? "Having parts on a shelf doesn't cost anything!" The problem is depreciation and unmovable stock. To get the part in the stock you have to pay, say, 100£. That's 100£ that is gone unless the part is sold for 100£. As new computer models arrive in the market, nobody want to pay that much for that same part. After maybe 6 months that exact same part may only be worth 70£. Try to change more, and the customer simply buys a new computer. You then have two choices. Cut your loss, and sell the part for less than it cost you, or leave it in stock hoping that somebody some day will need that exact part (this is a rare thing to happen). Multiply this with thousands of parts and you can see where the money go. To have any chance of making profit most companies either turn up their profit margins to allow for depreciation, or simply keep no stock. This is why it will take such a long time to get things fixed. Parts only get ordered when they are needed. No customer in the consumer market are willing to pay what it costs to keep parts in stock. For the business market there is something called an SLA (Service level agreement). That agreement may say that a computer have to be fixed within 24hours from failure. Such an agreement is incredibly expensive for the above mentioned reasons.