I somehow got my 15C's slip case wet and so the calculator sticks out the end a wee bit. And a couple of the rubber feel fell off and got lost. Other than that, it works perfectly despite being treatly roughly as well. Like yours, the keys are still in Day 1 condition. And like yours, I've changed the batteries maybe two or three times since I got it back around 1984, which is unfathomable to me.

It is probably the finest piece of electronics I've ever owned.