I worked for a ski resort property manager, with 147 units under management (from single-family homes, duplex, triplex, up to multi-unit buildings with pools) and a high-season rental pool requirement and we ran the water system and provided housekeeping and maintenance services (but we charged you for every light bulb other than incandescent, for every replaced blender, toaster, linens, etc) and we would stock your unit with groceries before your arrival and one of our staff drove the kids to school every day and we got paid as a school transportation service and handled the outgoing mail, etc, the same as a small village would need. 30% seems about right in a resort area.