Families with kids &/or or on longer trips, will have a need for doing laundry.
Many larger RVs have laundry facilities on board (either separate/stackable washer & dryer, or washer/dryer combination). Because of the volume of water used, this option requires water and sewer hookups. Some campgrounds prefer that you don’t use laundry detergent which could impact their septic system.
Most private campgrounds offer laundry facilities on-site.
In other cases, you may need to use a nearby launderette.