I have come to the conclusion that 'long life' oil is a misnomer. It should really be called 'long distance' or 'high mileage' oil, because it is designed so that a high miler rep need only have the hassle of servicing the car once a year. So why is it called it 'long life'?

1.To save a few letters

2. Possibly to suggest that non-long life oil has a short life and needs to be changed at least every 365 days, otherwise it will 'go off' !

There is plenty of information about microbial degradation of oil, and older posters will remember the smell following affected cars. Most of today's cars have small sealed tight engines and the oil gets so hot so quickly that microbes and significant amounts of water contamination just aren't a problem any more. The oil in my TR7 has been in over 5yrs, has done a mere 4000m and looks, feels and smells just fine.

Uncontaminated oil in a sealed container does not stop being oily, or change into something different. I have a bottle of Challenger sewing machine oil that is at least 50yrs old, and I guess many garages have a can of 3-in-one dating from the last century which is still capable of lubricating a cycle chain satisfactorily..

Lots of people do.

I saw a BMW 320d in BCA last year. 3 years old, 290,000 miles on the clock, and 13 oil changes - so 20k + between changes.

That's quite an impressive mileage - nearly 1900 miles per week on average. Someone spent a LOT of time behind the wheel!

The oil pours out the drain pan looking like gloss black paint so I do consider it worth it.

.....and so would I if my oil looked like that. Diesel, I presume.

Slightly different circumstances, but we change the oil in the race bike after three laps!

But then again it is the Isle of Man TT, so we have done just over 113 miles, 65-70% being at full throttle, (15,500 to 16,000 rpm).

It doesn't tale long for any lubrication issues to make themselves known, the usual give-away being half a con-rod poking through the front of the crankcase.

Speak to owners of high mileage vehicles and the vast bulk do very frequent oil changes. Almost every taxi driver I know does it every 10k or less,

Diesels, I presume. I would, too, as I think diesel engines are harder on oil and certainly contaminate it more.

our buses get an oil change every 28 days

If they are doing between two and three thousand miles a week, I would agree that's about right.

Longlife servicing was introduced as a means of cutting costs and downtime for fleet users. It was never intended for the longterm....

Well, actually, it was. And I was rather hoping for some input from high milers who used it.

Extending drain intervals shortens engine life - it's as simple as that. Yes modern engines can last a long time even with extended drain intervals - these extended service intervals are purely to make the the car more financially desirable to fleet operators - not the ultimate longevity of the vehicle - which is more important to 2nd onwards owners.

It's no coincidence there have been a lot of cam-chain issues with cars running extended change intervals. To prevent oil filters clogging over long intervals, modern filter elements are actually more porous than filters of old allowing particles under a certain size to pass through the filter to be suspended in the oil instead - so over time you are turning your oil into grinding paste - which I'm sure cam chains won't like very much. In a nutshell, change your oil and filter between services and your engine will last longer - perhaps avoiding cam-chain failure if it's not a "belt" engine - cheap insurance in my book.

Simple reason, oil is so cheap..... I say that since its only adding a tiny percentage to my annual bills and its better for the car I will continue to do it.

That is where we differ (and maybe also John F). For most people it seems that the main method for decision-making is purely monetary, presumably because that is the only simply quantifiable way. Many years ago there was a brief vogue for 'asset accounting', which I personally see as valuing things for their potential - I don't like throwing materials away before they have been fully 'used', and of course these days they must be correctly recycled.

The oil that you replace every 12 months has taken perhaps millions of years to create, and is essentially fossilised solar energy which you (and all of us) are re-using, much faster than it is being regenerated. So I judge when to change my oil, rather than assuming that the way I use my car means that the maker's annual recommendation is the right one for me.

<< 120 times as much petrol as engine oil. So do I feel guilty, not at all. >>

So you feel a bit 'guilty' about the petrol then ? :-)

There's far more oil than they let on - "peak oil" is a myth to keep prices up - certainly several centuries worth of oil left, which will out-last western civilization which is busily committing suicide, so there will still be plenty of oil left in the ground when what's left of mankind are dying of disease and starvation after overwhelming and destroying the culture that currently heals and feeds them.

Have you been on the conspiracy websites again? LOL