How likely am I to need 30amp and/or water extensions?

We carry two 25' 30A extension cords and a 50/30 dog bone, as well as 20/30 adapters. We also carry 75' feet of fresh water hose and 40' of sewer hose, along with about 200' of satellite/cable coax. We've only needed all of it a few times over the years, but we were darn glad we had it when we did need it. Sometimes having the extra extensions has made the difference in being able to park the coach a bit unconventionally to take advantage of a great view, particularly at some state and national parks.