I last changed my oil (BMW synthetic, 5W30) in Jan 2007 & have only put 2700 miles on my garaged '99 528i since then. Mostly 10-20 mile trips at hwy speed (70-80 mph) in the SE US. Should this be done annually regardless of mileage? Why? Thanks. bg
Should be done annually simply because the oils changes when exposed to air and the byproducts of combustion. It turns acidic (so they say) and should be renewed every year. Up to you, though.
Do it anually unless you do an oil analysis. Acid comes with combustion not sitting. I'd bet you have more water than normal. That's what I would be scared of.
I'm old and slow but isn't oil still cheaper than major or even minor engine repairs? Not only that, but don't you get to drive your car to a place where it is done for you, if you don't DIY?
