Revised by BoatUS editors in June 2012
As with all your rigging, careful, regular inspection of your standing rigging is very important. Like servicing your car before a long trip, taking a look at your shrouds and servicing them means that you shouldn't experience any problems underway. You can never be too careful - frequent inspection can help prevent big headaches and costly repair bills later on. Things to look for are cracks (even tiny ones) rust or any other sign of corrosion. Crevice corrosion is an insidious danger because it is often hard to see. It is a very good idea to have a qualified professional inspect your standing rigging regularly.
Common culprits for losing a mast are wire terminal fittings that have been weakened by crevice corrosion, rust and rusted chainplates. Also, don't overlook the smaller parts, such as lock nuts and clevis and cotter pins. It's amazing how much damage one of these seemingly insignificant pieces can cause. Don't take any chances with them! If they look dubious, replace them immediately. This is a far cheaper alternative than dealing with a total rigging failure.