The most important factor in determining whether a computer is too old is its ability to keep up with the latest software. According to Moore's Law, the computing power of a computer doubles every two years. This means that an 8-year-old computer is 6% slower than a new one. Although this decrease in speed may not be noticeable, it can still affect the performance of the computer.
Furthermore, most new software is designed to work best with the newest computers. While they may still be compatible with older computers, this can put a strain on the computer's resources and cause it to run slower than usual.