tl;dr Which is best? Buying high-quality, longer-lasting, but more expensive oils and changing oil less frequently or buying lower-quality oil but changing more frequently?

As I'm trying to find my way in engine oil land, I am basically stuck at the following dilemma. I own a BMW E46 from 2001, so in my example, all of the oils I'm talking about are fully synthetic and at least BMW-Longlife 01 approved. There are high-quality, but expensive oils that claim that they last longer than conventional oils (and this claim is BMW approved). With a little bit of simplification (not taking into account the negligible price of an oil filter and rounding prices a little), I can choose to:

  • either buy the more expensive oil and do oil changes only every 10,000 miles/15,000 kilometres;
  • or buy the cheaper oil (1/2 the price of the more expensive oil) and do oil changes every 7,500 kilometres.

As you can see, the overall cost would, more or less, remain the same, so I'm wondering which option would be best. Since price doesn't make a difference, and I don't mind doing oil changes more often (it's only 15 min. of work, after all), so what is the best option to prolong engine life?

EDIT: I was mostly interested in the general case, but in case any of you really know a lot about specific oils, these are the two oils I was talking about:

  • possible duplicate of Do different brands of the same oil really make a difference?
    – MDMoore313
    Oct 24, 2013 at 14:18
  • 2
    Unfortunately, you've asked an unanswerable question: there isn't enough data here for someone outside your specific situation to give you the "best" answer. The answers will tend to be based on opinion and that's specifically covered in the FAQ: mechanics.stackexchange.com/help/dont-ask Another potential duplicate would be: mechanics.stackexchange.com/questions/1079/…
    – Bob Cross
    Oct 24, 2013 at 15:04
  • If the change interval is within manufacturer intervals, I'd opt for fewer oil changes since there's less chance for something to go wrong (i.e. cross threading a filter or drain plug or dropping the oil jug and making a big mess on the engine and/or garage floor). Plus, I think few people can do an oil change in 15 minutes when all of the prep and cleanup work in included (including recycling the used oil), so time is probably a larger factor for most people.
    – Johnny
    Oct 24, 2013 at 17:45

2 Answers 2


It's quite easy. High-performance oils are meant to provide improved lubrication under, well, high-performance conditions while providing a similar level of lubrication "performance" under normal conditions.

If you're gonna drive like Dominic Toretto, then get the expensive stuff. But if you're only ever going to drive to work and back or take the occasional road trip, cheaper oils are just fine.

To answer your question directly: you won't enjoy the benefits of the more expensive oil unless you live your life a quarter mile at a time. But on balance, the more expensive oil is probably better because there's less maintenance involved and on the off-chance you're involved in a high-speed shoot-out with Columbian drug lords, you'll be glad your engine is protected.


Given the age of your car I'm assuming it's high mileage. That's really the only thing I'd consider - use a regular oil or one specifically for high mileage (HM)? HM oils are supposed to help prevent oil leak/seepage as seals get worn. I've heard that high mileage oil makes more of a difference to an engine than the synthetic vs non-synthetic debate. I don't have any hard facts but these two sites have some decent information.

My suggestion would be to use the cheapest high mileage oil you can find and change based on the car manual's frequency.

Mobil High Mileage Oil explained

Bob The Oil Guy forum

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