How to know the engine failure according to the condition of the spark plugs?

How to know the engine failure according to the condition of the spark plugs?
Spark plugs are an essential component of an internal combustion engine's ignition system. Their function is to generate the spark that ignites the air-fuel mixture in the combustion chamber. The condition of the spark plugs can provide valuable information about the engine's performance.

Inspecting the spark plugs:
Normal wear and tear: Over time and with use, spark plugs wear down and become less efficient. This can result in incomplete combustion, loss of power, and increased fuel consumption.

Deposits:…