There has been a lot of concern about the U-joints failing and particularly on the 2006 model year. Several have failed at the 10-12,000 mile range.
fyi - My WRV owners manual says "Inspect and lube the drive shaft every 16,000 miles". I lube the joints every 10,000 miles and haven't had a problem in 39,000 miles.
I like nice round service interval numbers that I can remember. If you follow WRV's recommendations you would have 7-9 different service intervals.
Our Jeep Liberty Diesels oil change interval is 12,500 miles (with synthetic oil), I use 12,000. My truck says 7,500 miles I use 5,000 because it does some towing. KISS