When the valve cover gaskets are leaking you will get a leak along the entire outer edge of the valve cover, which then begins to leak down onto the exhaust manifold(Main reason that the interior of the car started to smell of burning oil). There will also be significant leaking into the spark plug chambers of the cylinder head.
If still don't bother it, oil will leak out and make a complete mess off your engine and driveway(Such as steering housing boot, bushing and engine mounting). As oil level drops, your engine is losing valuable lubrication, hence it will start to destroy itself internally. Valve cover gaskets are cheap and easy to replace.
Sample Picture:
*The picture above not only valve cover gasket oil leak, but also the engine oil cap, link for the replacement part==>
HERE
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