There is not a lot of information to go on from the question as posted. When an engine is in proper operating condition, the spark plugs should not be "wearing out", on a regular basis. From the information at hand, I would suspect the wrong heat range plug is being used. Check to see what spark plug the engine manufacturer recommends for your engine.
No, but burning oil will give you bad spark plugs.
it means there is something wrong with the spark plugs cause they provide the energy for the engine
Oil on the outside of the spark plugs is caused by a leaking valve cover gasket. Replace the valve cover gasket. Oil on the electrode of the spark plugs indicates the engine is worn and is burning oil. The only fix for this is an engine rebuild.
Fuel burning is the burning of fuel. In an automobile engine it is called combustion. The gasoline mixed with oxygen and ignited by the spark plugs explodes.
Every gas burning internal combustion engine has spark plugs. Diesel engines do not. Your Impala is not a diesel, so it has plugs.
Internal engine damage.
yes definitely.
Bad engine cushions can make the engine shake. bad spark plugs cause malfunction as the car starts running.
spark plugs fouled with oil. blue smoke from tail pipe.
Worn spark plugs would cause mis-firing or non firing cylinders, both are no good for the engine, replacing the plugs may stop the knock (Could also be a different problem) But you should replace spark plugs as soon as possible.
Be sure to change spark plugs
Yes, fouled spark plugs can cause engine shaking, and loss or power. I'm not sure about knocking but I'd guess that too.