I just got new plates for my cuttlebug because my old plates were too warped and they did not make contact everywhere, and therefore all my dies were not cutting.
I also have a thin metal shim to use for intricate dies that seem to need it. Before I got that, I used a cardboard piece of packaging for a shim.
I have heard of Cuttlebugs getting looser over time, but unless it completely breaks somehow, I would think you could just add shims.