How Long Should a Desktop Computer Last?
A well-maintained desktop can reasonably last six to eight years or more, because individual parts such as the drive, RAM, power supply and fans can usually be tested, replaced or upgraded without replacing the whole computer.
Why desktops often outlast laptops
A desktop has more physical space for cooling, less battery-related wear and parts that are usually easier to access. A failed power supply, noisy fan, tired hard drive or low memory does not automatically mean the whole computer is finished. Those parts can often be tested and replaced individually.
The parts that commonly age first
Mechanical hard drives, power supplies and cooling fans are common wear points. RAM can become insufficient as software grows heavier, even if the memory itself has not failed. Dust buildup can make a desktop run hotter and louder than it should, especially if it sits on the floor or under a desk.
What eventually limits a desktop
The processor and motherboard are the practical limit. Once they are too old for the work you need to do, replacing smaller parts will only improve the machine around the bottleneck. That is when replacement starts to make more sense than another round of upgrades.
A sensible repair threshold
A desktop is a good repair candidate when one part has failed and the rest of the machine still suits your work. It is less attractive when the repair cost is high, compatible parts are getting awkward to source, or the computer was already slow and unreliable before the current fault.