Tameshigiri. I have a couple acres of bamboo growing on my property that I practice cut on all the time. Keeps me in shape.
As a backnote I have trained kenjutsu for 20+ years and I possess menkyo kaiden for my style. Menkyo kaiden is the right to teach/right of transmission.
I do have collector blades, my best is a 1321 Soshu Yukimitsu pushing $700,000.
If you look a few pages back you can see some of my other blades. I actually have a blade made in 1983 that is worth more than blades from the 1400's. Its not just age but the quality of the smith and the blade that determine the worth.