I have a set of tubular, 650c Zipp 400s that are lightly used by me (one ride of about 15 miles), along with a couple hundred miles by the previous owner. I have moved to a 700c so cannot use them.
They are a few years old, but the wheels have been well kept and are in good shape. A set of tires is attached, and I will include 2 spares, as well. 18-spoke front and 24-spoke rear.