I think that anything that you can do to create passive income is good. I know that laundry mats are a good idea. My family owns one and we usually profit about $2000 a month every month.
$2000 a month is certainly nothing to sneeze at. I wonder how much damage is done monthly or yearly from the clientele that visit laundry mats. Not always the cleanest or most polite people in them. I would be curious about the amount of damage that occurs.
The damage my family's facility gets is not bad really. Only about one time a year is there any maintenance needed to the facility and even then it is minor things like painting and repairing things you would expect through normal wear and tear. The laundry mat is on a main drag so that might help with the lack of damage. Last month we brought in over $2000 so it is great in my opinion. Just don't add one in my city though, don't want our profits going down. :>) I live in Carmel, Indiana btw. Seriously though I would look into the costs associated with purchasing or leasing all of the equipment and facility and check int if it is something you want to do, I would highly recommend it.