Protect your hoses and yourself from icky water.  Everyone uses the small, basic filters for those weekend camping trips.  Once you go full-time and if you stay in any park for over a month, this upgrade is more than worth it.  In addition to having to replace it less frequently, you can also select the different types of filters you may need, depending on the water you are hooked up to and using.   For instance, here in Florida it’s all about the chlorine and our smaller one just couldn’t keep up.  Now, we just purchase the bigger filter as needed and pop it inside the larger housing.  It has actually been less expensive as time goes on and that’s another benefit.