The night before they woke to a loud hissing noise and found that one of the faucet supply lines in their main bathroom had ruptured. Fortunately they were home at the time and were able to close the valve before any major damage was done.
What was interesting (and a little scary) about this particular failure is that the ruptured line was actually a steel braided hose!
One of the most common causes of significant water damage in a home is incorrect or "old" plumbing. Pipes buried in the walls should be inspected by a professional but there are a few quick do-it-yourself projects that should be added to your regular maintenance routine.
The one my good neighbour will now be doing is a routine check of all sink and toilet supply lines. Look for signs of swelling in the lines themselves or leakage at each end. If you see anything out of the ordinary, take a quick trip to the hardware store. Replacement hoses for most applications are less than $10 and these can be installed quickly with an adjustable wrench. Remove the old hose (after shutting off the water supply!) and bring it to the store with you so you can identify the correct length and end fittings for the replacement. It is also a good idea to replace any other supply lines to that fixture at the same time. Check for leaks immediately after installation and again periodically for the first few days.
While you have your head under the cabinet, check for drips or moisture at the shut-off valves. In some cases these can be fixed by tightening a connection. If that doesn't work, the valve may need to be replaced (which may require a call to your contractor or plumber.)