twice a year. I only put about 5000 miles a year on it.

Most people don't realize this, but the majority drive with "severe service cycle", which is defined as short distance driving, stop-and-go traffic.

The service schedule for oil, as published by BMW, is doomed from day 1. It is a setup for sludge.

As the car gets older, the piston rings are more loose, there is more blow-by combustion gases etc. So the service interval needs to be shorter, IMHO.

My driving is 50-50 city-highway.

I use Mahle oil filter ($5/each) and Castrol Edge oil (Home Depot, or Walmart). Occasionally I use NAPA Synthetic oil when it is on sales.

- Summer: 10W30
- Winter: 5W30

The X5 has 120K, so I change my oil every 4K-5K. I will do an oil analysis soon, just to see the health of the engine.

^^I'm with Pete and cn90, I change every 5k with OE filter and Rotella T6 5w-40 year round. Other than that I replace things when broken, and some preventative.

I don't think we should approach this as "cheap".
This needs to be done with "scientific proof".

- Take oil sample at 3K, 5K, and send to the lab for analysis. This will give you a baseline analysis of "your" engine, and not others' engine.

- Even the car gurus (Larry Carley et al) say most people belong to the "severe service cyle" and this is what they say:
* Standard oil: every 3K-4K
* Synthetic oil: every 5K-6K

OA is only really helpful when you trend multiple reports. And or looking for a problem and wanted confirmation by a one off report...

I used to do OA for every OCI just because, but decided to just spend my money on Oil instead...

Is this because we are "told" that motor oil is only 'good' for a six months period?
I have several cars that rarely get driven (summer cruisers) and sit in a garage most of the year. I choose to change the oil in them on an annual basis. On average, these vehicles would only travel about 5K kms a year though.
I believe oil has a limited 'shelf-life' and will deteriorate with time, both in an unopened container and in an engine.

I run everything on the 5,000 to 6,000 mile cycle of O&F changes or once every year regardless of mileage as some of the cars only see 500 to 2,500 miles. Mobil One 0-40 or BMW Castrol 10W60 for M cars. I use Mann filters. The X5 sees mostly what I would call severe drive cycles of trips less than 25 miles, hence oil is changed every 12 months or 2,500 miles. (The Dodge Minivan gets Mobil One 10W-30 every 6 months or every 5,000 miles whichever comes first). If I follow the BMW idiot lights, I would be doing oil services every 3 years or so.....:yikes:

This service is inexpensive and should be treated as critical for long life. Hell they are over 10 years old now, so what is long life now days? My personal goal is to never have an issue by doing all scheduled maintenance and service checks before required. Tends to resolve "incidents" on the vacation trips.

Most of the posters here on the site are following similar patterns of "better than recommended" maintenance on our X5s with results that speak for themselves. Unfortunately, I like others have seen cars with up to 30K with the original filters still in the car. They are not functioning real well, but they are still where the factory left them. I am always amazed that BMW builds them so well that they will still run with that type of abuse. Lights on all over but the driver just ignores them. Now I would not recommend buying one of these vehicles as the lack of care extends all over from trashed interiors to exterior lack of washing/waxing. Dents and scrapes

I agree with those that believe frequent oil and filter changes are a wise investment.

I change oil every 5000 miles. I always change the filter with one from BMW. At over 114,000 miles I use about 1/4 qt. per change. I use recommend weight oil. I do use the same oil every change.

I don't think all full synthetic oils are created equal. I do think any brand name synthetic is more than adequate with reasonable oil and filter change intervals.

I vaguely remember reading sometime ago, that Castrol or Valvoline was take to court in the US over the use of the word 'synthetic' describing one of their mineral based oils that had been "super-refined". This doesn't alter the fact that this was still a mineral based product, despite any level of refinement. One reason I generally use Mobil1 products I suppose. Australia also has a very good fully synthetic oil manufactured locally. "Penrite" has similar qualities to Mobil1 and compares favourably in price to other 'so called' synthetic oils. I use their 5W 40 high zinc in my diesel driven vehicles, as it meets VW, BMW, Mercedes, Audi specs.

Oopsie, I didn't think it necessary to mention I was talking about full synthetics. Previous post edited accordingly.