Castrol engine oil

The seal is unbroken - but the fact that there are mixed views on this matter worries me. I only learned recently that you need to have your oil changed even if you haven't driven much because, as a mechanic told me, "oil goes off whether the car is driven or not".
Of course if the oil is in the car, the seal is obviously broken - but the jury is split on the "expiry date" issue. I mean, why would reputable oil companies say "Don't use after the expiry date"? And why does it have an expiry date at all? When you buy a windscreen or a door handle, or a wheel-nut they don't have "expiry dates"?
I think it should be illegal to sell oil with no expiry date - and in my case, there's no "manufacture date" either.

In fact no dates at all!

But thanks anyhow.

It's a tricky one. Anyway, thanks for the advice.

I've decided to give it as a Xmas present to the garage that do my servicing. That way, it won't go to waste.

Just out of interest - in case someone else has the same issue. I got in touch with Halfords (England) and also a garage in the midlands which sells loads of this particular oil. They both assured me that a number which is almost invisible - but can be felt - shows the manufacture date. Sure enough there is an embossed number on the container and the date is recent. So the oil is fine after all.

The date is the same colour as the plastic so it's dead easy to miss it. I was sure there was no number or date.

I'll know the next time what to look for.