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While WAPs can degrade over time, you are more likely to be hindered by outdated technology/protocols than the aged internal components. WiFi uses precise timing in order to send/receive signals to/from your devices, avoid collisions, and even triangulate your device's location (with newer WiFi 6 protocols) for more efficient transmission. It is possible that the timing component, usually a crystal oscillator, can degrade over time due to an aging power adapter supply or a very RF (radio frequency) noisy environment. Nevertheless, it is likely outdated technology/protocols that are slowing down your connection and not the physical health of your WAP.
You should consider replacing your WAP when the number of devices increases, or your use increases and you are having trouble staying connected or your speed is much slower than a wired connection.