I have up to an 8 hour delay on mine and I use it all the time. It won't hurt the washer. I throw the load in the AM before I leave and set the timer. It's washed and ready for the dryer when I get home. I don't worry about the washer running when I'm gone as it's right by a floor drain, but I don't run the dryer when I'm gone because that involves a 220 current in an appliance that has to heat up.