Ask anyone who has cleaned up after a burst washing machine hose and they will tell you the same thing. It did not look worn. It looked fine right up until it did not.
That is the trouble with appliance supply lines. They sit behind a machine nobody moves, under constant pressure, twenty four hours a day, whether the appliance is running or not. Rubber hardens. Fittings loosen. The failure point is almost always near the bend at the connection, where you cannot see it without pulling the unit out.
Replace on a schedule, not on appearance
Here is the rule that prevents most of it. Age is what should trigger the swap, not how the hose looks.
The Insurance Institute for Business and Home Safety puts washing machine supply hoses on a three to five year replacement cycle, and recommends upgrading to braided stainless steel when you swap them. Dishwasher hoses get five years. Refrigerator supply lines get inspected every six months, as does the water heater. That is a fifteen minute job with a wrench. The alternative is a subfloor.
What to look for when you check
So what should you actually look for during those checks?
Blisters or bubbling in the hose wall. Stiffness where the hose should flex. Rust or mineral crust at the connection. Any dampness at the fitting, even a small ring of discoloration on the floor. And check that the shutoff valve actually turns. Older screw type valves seize in place, which means the one time you need to close it quickly, you cannot.
If you find soft flooring, swelling at a cabinet toe kick, or a musty smell with no obvious source, the inspection window has already closed. Water has been sitting long enough to reach material a fan will not dry. That is the point where water damage from a leaking appliance in Elk River stops being a maintenance question and becomes a moisture mapping question, because the wet area is almost always larger than the visible one.
The other appliances that fail the same way
The same logic applies to the rest of the water connected appliances. Dishwashers fail at the door gasket and the drain clamp, and the water runs under the cabinet where nobody sees it. Refrigerator ice maker lines are thin plastic and develop pinhole leaks that drip behind the unit for weeks. Water heaters corrode from the inside and give very little warning before the tank lets go.
None of these announce themselves. That is the problem. By the time there is a visible puddle, water has usually been traveling along a floor joist for a while, which is why a ceiling stain below often shows up several feet from the actual leak.
Habits that cost nothing
A few habits that cost nothing:
Do not run the washer or dishwasher when the house is empty or everyone is asleep. A hose that fails while someone is home is a mess. The same failure at two in the morning while you are away for the weekend is a different category of problem entirely.
Leave four inches of clearance behind the washer so the hose is not kinked against the wall.
If you are away for more than a couple of days, close the supply valves.
The full checklist runs longer than most people expect and it is worth reading once. IBHS publishes its guidance on preventing interior water damage from plumbing and appliances free, broken out room by room, including water heater flushing intervals, anode rod replacement, and what to check at a toilet. It also notes something worth sitting with: washing machines and dishwashers now last an average of twelve to thirteen years, down from what they used to.
One last thing. Write the replacement date on the hose with a marker when you install it. Five years is a long time to trust your memory, and the hose will not remind you.