I've had some bad experiences with my L494 5.0 V8 SC that could have been avoided with some preventative maintenance. The little bit of pre maintenance I did i gleaned from posts all over the interwebs.
So, for posterity and the future owners of nice, but out of warranty, luxury SUVs I thought a thread like this would be a great resource.

Anything new posted on this thread I'll add to this post to create a list.

I'll start:

1. Transmission fluid change and service.
LR says the fluid lasts forever, it doesn't. Preferably take it to an engineering shop that specialises in the ZF box if that's the gearbox your RRS has. Will save you 20x in the long run.

2. Coolant pump and pipes.
Replace the coolant pump and have all the hoses inspected and replace anything that looks dry or cracked. The cost of not doing it is about 80% the purchase price of the car (depending on year model and the extent of the catastrophe that your engine will turn into suddenly).

3. Sunroof Drains
Inspect the sunroof drains. There's one on each side. A search on this or other forums will show you how to DYI get to them via the roof liner or how your local panel/autotrimmer could get to them and preferably replace them with copper fittings and epoxy. They corrode around the drain nipple and one day your car will be outside when it pours down and that corrosion will let half the water through into the bodywork which could be as minor a wet fuse box or as major as your car becomes a porta pool.