This got me thinking and so I've been reading but only from reliable sources such as oil companies (no internet subjective stuff). Oil company recommendations vary a little and, obviously, they have a vested interest in being conservation to ovoid issues and also, sell more oil.
A quick synopsis is that, in a sealed container and not subject to excessive heat, oil is safe for 5 years, after which it should be examined before use. Basically, if it looks alright and smells alright, it's still safe to use even beyond the recommended shelf life.
The major time related issues seem to be separation and oxidization. Separation is from just sitting, so the container doesn't seem to make a huge difference. Oxidization is from air exposure, which is obviously less in a sealed container - the question is degree. Oxidization accelerates significantly as the hot oil is churned around a running engine. One quote I found, "Oil does not degrade significantly just sitting in a cold engine". Draw your own conclusions.
Personally, I wouldn't be concerned but, if I was, I'd use a tube down the dipstick hole to take a sample. If the oil hasn't clumped, doesn't look cloudy and smells normal, I wouldn't worry. However, I do concur that an oil change is cheap insurance.
I'd be interested in any expert opinions, otherwise, I'm out.