Here are my thoughts:
I've replaced oil and filter on my 2006 RRS every 7500 miles, as recommended by Land Rover (I drive lots of miles and hit 7500 every 3 - 3.5 months on average... My new car warranty is gonna be up in less than 2 years!) However, the 4.4 liter on my 2006 - shared with the LR3 - doesn't use the fancy synthetic oil of the new 5-liter engines, so I can understand the longer service interval.
I've replaced rear locking differential oil and x-fer case fluids on my Sport every 75K miles (as recommended by Land Rover), center diff and transmission fluids once at 120K (Land Rover recommends every 10 years or 150K miles, even on the new LR4. It's not a "sealed for life" tranny, although for most owners it might as well be with such a high service interval...) Every other item on the service schedule was checked / replaced per Land Rover's recommended schedule, I didn't stray that much. It's worked just fine for me, I have 210K miles on my Sport and its engine, transmission, transfer case and differentials are still the original ones and have been completely trouble free. I've had some problems with suspensions over the years (replaced a couple of shocks, a truckload of front and rear sway bar bushings, LCAs once, and an EAS compressor back when the car was still under warranty), some other minor body hardware and various electronic gremlins, but nothing out of the ordinary for a high mileage car such as mine. Overall, my RRS has been - and still is - a fantastic, reliable car.
For my new LR4 I think I'll stick to Land Rover's recommended schedule of 15K miles between oil changes personally (which will mean about every 6 - 7 months for me.) 90% of my mileage is from freeway and city driving, I don't race 24/7, drive in mild temperatures pretty much year round, don't pull any trailers and I go off-road perhaps every couple of months, tops. No arduous conditions for me. I'll have all scheduled and unscheduled services performed by a local indy Land Rover mechanic, a former JLR Master tech who opened his own shop: He charges 20 to 40% less than a stealer here in So Cal, uses original parts and has all kind of official and "unofficial" diagnostic tools available in his shop if necessary. Most of all, I trust him. I don't plan on visiting a dealer except for the first freebie at 15K miles and any warranty or recall work thereafter. Based on past experiences, I just don't trust any of them and I think they are ridiculously overpriced. I am lucky to have several competent independent mechanics specializing in Land Rovers in my area, many other owners are probably not so lucky. I'd love to perform my own tune-ups, but I just don't have the space or time to do it. If you do, that's great.
Your mileage may vary.
You should be safe by doing oil changes yourself and keeping records of oil used etc, unless the dealer says you did it wrong and your engine melted down because of it...
