The condition of the heating elements is important. The elements should not sag out of the grooves.
Elements are not difficult to replace, though. A more important consideration in buying a used kiln is the condition of the bricks. That is a good indicator of how well the kiln was treated. If the bricks are in mint condition, the kiln was cared for.
Also, bricks are difficult to replace; elements are comparatively easy.
Another important consideration is circuit wiring. Will you need a new circuit installed? If so, be sure to install the circuit recommended by the manufacturer. For that, you will need the kiln's wiring diagram.
The reason I mention this is that Paragon A-series kilns (last made in 1987) use the 4-wire system. Some electricians insist on installing a 3-wire circuit for the A-series kilns. But the 4-wire system is safer. You should be aware of that when buying a used kiln.
Sometimes, the used kiln will have the wrong cord. So before installing the circuit, look at the wiring diagram. Don't depend on the cord plug as a guide.