Summarize this article in one sentence.
To prevent damage, the cooling system needs to be carefully regulated. The more stress you put on the components, such as the processor, video card, and hard drive, the more heat they generate.  For the average user using a factory manufactured computer, heat build-up isn’t usually a major issue. When you’re building your own computer, or upgrading an existing one, temperature and cooling becomes an important concern. The older the computer becomes, the more prone to heat failure it becomes. Cooling systems will degrade and fail with age, and dust can seriously hamper heat dispersion. If components become too hot, they can become permanently damaged. This can lead to system failure and data loss. The temperature threshold varies from component to component. Average temperatures in a well-cooled system should be in the 40–60 °C (104–140 °F) range. There are a variety of ways to improve your computer’s ability to cool itself. The easiest method is blowing out dust from the inside of the computer using compressed air. Dust will cause fans to slow down and hinder the cooling properties of heat sinks. Dust your computer regularly to keep it running as cool as possible. If you are using a desktop computer, you may be able to install more fans. This will require opening the case and connecting fans to the case and the motherboard. Check out our guide on  installing fans for more information.

Summary:
Understand that high temperatures can damage components. Know that the acceptable upper limit for component temperature is generally around 80–90 °C (176–194 °F). Improve your computer’s cooling.