The answer to 'supply line maintenance' is to regularly inspect and maintain your plumbing supply lines to prevent leaks, water damage, and costly repairs. Supply lines are the flexible hoses that connect your major appliances like the washing machine, dishwasher, and refrigerator to the home's water supply.
You should visually inspect your supply lines every 6-12 months for any cracks, bulges, or signs of wear. Replace any damaged or old supply lines, typically every 5-7 years. When replacing, use high-quality stainless steel braided lines which are more durable than standard rubber or plastic. Also, make sure to turn off the water supply before disconnecting a line. If you're not comfortable doing this yourself, call a professional plumber to inspect and replace your supply lines.