I wanted a KLR or a DR650 as a second bike to my 2012 DL650. Something I could just use for zipping around town, getting groceries, local exploration, etc.
Ended up with a low mileage, well set up 2005 DL. It turns out to be an awesome bike and I ride it more than I do the new one. I don't think it is more expensive than any other "second" bike would be and in some regards, it is cheaper. I am upgrading the suspension on the new bike with after market parts and will re-use the 2012 components on the older bike.
Wish the seats were interchangable, but many of the parts work. I save my nearly used up tires and finish them off on the older bike, on local rides, or at least that worked out this year. I plan to start the year with new tires on both.
I tend to "over do" my maintenence and there is always one bike undergoing some adjustment or upgrade so it is nice to have the other one ready to ride.