@Diana-and-Ryan0 My 'forward thinking' has taught me, at least in my place (an island, 6 miles from mainland) that kids: get into everything and break things constantly, tend to spill things (including on the new mattresses), be on the Internet streaming all day long (bandwidth, $5 a gig), leave every light/fan on all day (power use, run out batteries, now have to use generator), eat constantly (dishes = water), in and out of the water all day (use outside shower for rinsing and playing = more water), use the snorkeling gear & kayaks and forget to bring them back to the dock (free $1000 kayak for some lucky soul in Honduras 2 days later), etc etc.
I encourage families, in fact, I promote my place as a 'kid's world' which it is, but they do come oftentimes at some serious extraordinary added costs.
(P.S. Water is 8lb per gallon, to buy & transport comes to about $.30 a gallon to an island: , couples use about 40 gallons per day, 2 couples about 70, family with kids about 125-150 gallons a day or 1000 lbs of water per day!).