Cracked power cords
Obviously, power cords don’t go off. Like all electrical items, however, ensuring they are in a safe condition is important to keep your home safe from fire risk. If your cables are worn out and near flammable materials then you may have a problem.
Check them regularly for cracks or visible wires, and that the connectors are in good shape. Replacing any that look particularly worn is much safer than running the risk of waiting until something breaks properly. Even though you can replace worn-out cables with new ones, this might not be the best option since the appliance may be too old to work optimally.