Mine has a rough area on top which seems to be spreading to other areas on the steering wheel. Started at around 20,000 miles now at 46,000. I don't like covers but I may need to look into one.
my last truck was an '01 ( 3/4 ton gasser). The wheel cover was perfect for 100,000+ miles.

 

no rings, no greasy hands, but the two ive killed myself wore out at the top where i always keep my hand

 

The dealer replaced the steering wheel on my 03 under warranty. The leather kind of crumbled or delaminated.

I don't wear rings, and I am fussy about keeping the truck clean (I always scrub my hands after chaning the oil, for example).

I suppose I do have sweaty hands at times...

So far the 06 has been fine, but there is a bump under the leather, like they got a chunk of debris in there when it was stiched up.

 

Bad alignment and fighting it caused it in my truck I'd imagine.

 

Mine a SLT didn't come with a leather wrapped stearing wheel but I wrapped it with a Wheel Skins two tone cover. I like the feel of leather and the slightly larger diameter. They can be a bit tough on the hands while installing "my pinky finger was a bit sore" so some may want to wear thin leather gloves.