Many people like to operate their washers, driers, and dishwashers right before they go to bed. They take advantage of cheaper electrical rates and wake up to a chore already done. I use my appliances when I'm awake and at home and am watchful for noises and/or longer running times. It doesn't happen often, but sometimes an appliance malfunctions and results in a fire or flood. Just this week, an inlet valve on my underground sprinkler malfunctioned. If I hadn't been home, the sprinkler would have just kept running, and I would have had a ruined lawn and possibly a flood in my basement. I've had this sprinkler for many years with no issues, but there's a first time for everything.