Back as I was writing my undergraduate thesis, I was also very enchanted by the concept of rates of decay. At one point, the theory of exponential decay composed the introduction of my entire thesis project. Then it was demoted to the acknowledgements section, and then entirely rejected...poof. Its role in my thesis had several half-lifes--losing energy and significance with each proofreader reaction and each replacement.
But thinking about exponential decay: "a quantity is subject to exponential decay if it decreases at a rate proportional to its current value"
I like to muse over all of the exceptions to the rule. The value is relative to each person, and an item might undergo exponential decay for one, but exponential growth for another. Classic cars, antiques, pieces of art, photographs, etc.
At our ranch, there is an old house. It is uninhabitable. My mother is having it torn down sometime soon. The value lies in the wood. Not in the building itself, not in its role as a home, not in the meals taken indoors or the views from the bedroom window. It has been reduced and I guess that is it. I like it though.