Yes, a little flippant of me. When we consider that modern engine oils are made to survive for 12 months in the harsh environment of a petrol or diesel engine, it shows the quality of engineering that has gone into the production of them. Engine lubrication isn't a closed system - there are 'breathers' through which volatiles can escape, which is just one of the many things which causes oil to degrade, but still they are made to last for twelve months or more.

It follows that oil in a container which is sealed to prevent the escape of volatiles should easily last for a decade and still be good for purpose.

Twelve months? I've seen some service intervals of two years.

I'll also put my apology in too - my comments were somewhat sarcastic.

Are we back on the 2 year service interval again ? Not for me, old boy, I prefer my engines to have a long lifespan, not longlife servicing.