I suppose if I ever needed it in town as a backup rifle, then that's a side benefit of having it in the truck.

You'll notice the light coating of dust all over it. Of course, I periodically clean the rifle, but, is it a good idea to treat an AR-15 this way? Also, after an entire summer in the truck the optics seem fine, despite pretty high temperatures.
As a side note: when I go to town, I throw a towel over the rifle so nobody knows what's there.