Is the pentax hd da 560mm f 5 6 ed aw worth buying used?

Here is what the site says about that.

From Pentax HD DA 560mm f/5.6 ED AW: Pentax HD DA 560mm f/5.6 ED AW: A prime lens by Pentax for APS-C cameras, 560mm f/5.6. A super-telephoto prime for birds and distant wildlife. Specs - Maker: Pentax - Focal length: 560mm (prime) - Maximum aperture: f/5.6 - Made for: APS-C sensors - Mounts: Pentax K - Stabilised: no - Autofocus: yes What it frames like - On APS-C (Pentax K): like 840mm on full frame; f/5.6 gives about the depth of field of f/8.4 there. ...

From Buying used: Buying used: Cameras and lenses are built to last, and many photographers upgrade often. That makes the used market one of the best ways to afford good gear. A body that's one or two generations old is often most of the camera for a fraction of the price.

Quoted from this site's pages.