Last fall, I had the bolts on one of my chainplates fail, and that led to a mast hinge failure and a neutrally buoyant DSII. It took that as an opportunity to upgrade my stays, and because of the larger clevis pins, I replaced the chainplates too. I think that the chainplate that failed was original, and one contributing factor may have been stays that were not adequately tensioned, which led to some significant loads while on mooring.
Today, as I was removing the other chainplate, one of the bolts snapped too. If you are upgrading your rigging, or looking for cheap maintenance, I would highly recommend replacing/upgrading your chainplates. I ordered new chainplates from D&R, and had them include new bolts too. The new bolts are beefier, and the stay attachment holes are drilled to match the diameter of the thicker clevis pins on the upgraded stays.
Definitely a cheap upgrade that reinforces a potential failure point.