To us seeing everything we want to see has little to do with how long we would keep our RV. We have it to camp out whenever we can fit the time in ... even if it means going back to the same places. A good spot to camp is a good spot to camp. We know a great camping spot when we see it ... but it's kind of hard to describe it objectively ... other than away from crowds.
However, the main reason we go on RV trips is for a change in environment - even though our stick house is very comfortable and is already in a beautiful wild lands place. The sense of freedom and laid back feeling we get on an RV trip cannot be matched in our stick house. Besides, our beloved pet passed away after RV'ing with us for years ... and her replacement just has to be taken back to see the same camping spots! ;)