An RV is like a tool IMHO and once you decide what job will be done with it, then size and style can be decided upon. We are a small family of three with two dogs and for us 25ft is a good size BUT we are mostly weekend warriors who frequent state and national parks. With that in mind, state and national parks do have size restrictions and very limited space for bigger rigs of any at all. However, if you will mostly be staying at RV parks then 40 feet isn't that big compared to the big rigs we have been next to at 50-60 plus feet and shouldn't present issues most of the time. Happy hunting and good luck with your purchase!