Here are a few mast failure stats from my microcosm here on the central coast:

We encounter about 3 boats a year that have been dismasted due to anchor pins breaking (Most common source of rig failure).

We encounter about 2 boats a year that have a catastrophic rig failure due to quick pins unexpectedly parting (Always a shroud). We see another 2 boats from wire breaking at the interface with a rollerswage (Always check for cracks and replace at factory prescribed intervals).

We encounter about 1 boat a year with rig failure from people that make their own rigging at big box marine and the swage pulls out.

And usually every other year we will encounter a mast extrusion breaking.(Carbon masts are not included in this data)

About every 2 to 3 years a ring will pull out of the pin and someone will loose a rig.

There are a few other uncommon reasons people loose masts in the miscelaneous category:

Installed furler upside down (TheMightyHobie18). Dropped mast after loosing control of it in the parking lot (actually quite common), etc.

Moral of the story: Don't use quick pins for standing rig, change your anchor pins/ inspect chainplates, get new wires every now and then, and hang on to your rig when you're raising it.<img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" /> <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

Hope that helps.