The other day I was at my local supermarket coffee's corner and met a nice & funky inter-coastal BMW nomadic rider muddy, dusty and dirty as hell who repeated me at least 5 times as an anxious friend advice and obsessive topic to LUB THE SPLINE ! LUB THE SPLINE ! LUB THE SPLINE !
Is there a recommended interval for that ?
Another friend told me yesterday that if the spline is not lubed it can suddenly fail around 60K and in the process ruin the gear box which end up being NIGHTMARISHLY EXPENSIVE to repair.
So far - that doesn't seem to be a hexhead issue. It was for sure an issue with the brick-K-bikes, and with some (not all) oilheads. I haven't heard of any clutch spline failures on a hexhead, and some of the early bikes from '05 are getting serious miles on them. The driveshaft also shouldn't be a problem point since BMW finally figured out how to put the pivot points on the paralever arm in the exact axis of the U joints - which means the splines don't slide since the length stays the same as the swingarm goes up and down. Without sliding - the grease lasts WAY WAY longer, and even without grease (some people have reported this) - no one I've heard of has worn out a set of splines that I have heard of (and I'm fairly well plugged in to the hexhead tech stuff..)
Sounds like well meaning advice - but the wrong bike.
Don Eilenberger - NJ Shore
2012 R1200R - I love this bike!
Yeah...the guy was very nice but he was only riding "old" kind of refurbished bmw's.... but he really looked quite traumatized bike this failure detail. He is from east coast riding all the time and looking like he also sleep on his bike...
The monthly article in the BMW Owner's News that is written by the man that sounds somewhat like the person you described recommends 40,000 miles for current models. It is needed less frequently on newer models but much harder to perform.
2014 R nineT,
2011 Grey Matte R12R, (at the beach)
2011 Red R12R (RIP), &
'09 White R12R (RIP)
LUB THE SPLINE ! 
LUB THE SPLINE ! 