Do you wonder why your car rides poorly? (springs)

[Kube]

Here's an example as well as a reason I install NOS springs in all of my restorations.
This spring (main leaf shown) is from a 34,000-mile car. The problem? It is from an 89-year-old car. A long time for all that weight pressing down on a spring.
One look at the main leaf from this car next to a NOS main leaf and it should be apparent why it's necessary to replace tired springs.
Springs are designed to carry a specific amount of weight and thus to offer a desired (read: designed) handling and riding characteristics.
I once sold a '40 convertible I'd restored (unadvertised) as the guy that wanted it took notice of how much higher it stood vs. all the other '40 Fords at a national meet.