Knowing how to select a cooling system for a gaming PC will preserve its long-term life. Overheating is one of the main reasons why hardware fails. There are several factors to consider when selecting a cooling system. If you don’t do your homework, you can end up buying something that doesn’t meet the cooling requirements of your system or buying something that doesn’t fit properly.

Liquid Cooling vs Air Cooling
There are two types of cooling systems to choose from. The first and most common is air cooling systems. Air cooling systems have a lower capacity to cool but are less expensive than liquid cooling. Liquid cooling systems can do a better job of cooling but only focus only focus on a specific component like the CPU. They are also more expensive.
TDP
Thermal Design Power (TDP) is the standard measurement for heat in CPUs and other computer equipment. AMD and Intel both list the TDP under their system specifications under each processor. When selecting a cooling system, you will want to make sure that the TDP of the cooling system is higher than that of the processor. If it is lower than the processor, the cooling system will not properly cool the processor and may lead to blue screens, crashes, warnings, and ultimately shorten the lifespan of the processor and other components.
Cooling the graphics card, memory, VRAMs, SSDs and other components
Modern motherboards come with additional heatsinks and ways of cooling the system, such as adding multiple layers of insulation between copper paths. The higher the PCB of a motherboard, the more cooling protection it provides (e.g. PCB 6). PCB stands for printed circuit board and the number following it describes how many layers are included. These layers act as insulation.
Higher end motherboards will also provide additional cooling through VRMs (virtual regulator modules). VRMs provide power conditioning to the CPU and other components, making sure that stable clean power is delivered. These VRMs sometimes get overheated, so you may find that some motherboards include heatsinks for them.
Heatsinks and radiators can also exist specifically for M.2 NVMe SSD storage, RAM, and graphics cards. Cooling these components will also lead to a longer life-span of the entire system, especially for any overclocking plans.
A good recommendation is to get a mix of heatsinks, liquid cooling, and fans. The more you do to cool your system, the better longevity it will have. If you are spending a lot on a custom gaming PC, spending the small amount of extra money to preserve your system is worth it.