There are no blaring problem areas. If the boat is setup right, maintained, and sailed in non-life challenging conditions, you should not be faced with any predictable failures.

Key is knowing your boat and prevention. Before every sail, inspect the rig especially the fittings. If the rig goes, your sail is toast. Be sure the ring dings are taped and not misshaped. Inspect the spin pole stays. Make sure the forestay is well fastened to the bridal. You'd be surprised how taped ring dings become freed and just ready to snag the spin sheet or a tensioned forestay shackle will work its way loose.

Thereafter, most breakdowns are the result of hitting something in the water or related to a capsize, i.e. crew/skip going through the sail or boom, hanging onto the tiller, or debris after a storm (coconuts). After righting after a capsize, inspect all of the rig fittings AND the spreaders, sometimes they will move and will not be able to support the pressure while under sail.

Now if you are like Karl and traveling 1000 miles for a multi day event, it is wise to carry spares. Karl probably has spares for most of his spares. I don't blame him.

Finally, if your sailing season is seasonal or you traveled a long distance for a multi day sail/event, do a good shake down sail before that big event or friends get together.