I have young kids and often mow after 9pm because that's when I finally got them to bed so I can do chores. The noise doesn't make much of a difference to them. I'd be surprised if my neighbors cared. I worry much more about my neighbors sanity listening to my kids play in the backyard during the day. Constant laughing, yelling, crying, etc.... rivals the annoyingness of a dog. Give me lawn mower noise anytime.