I know where your wife is coming from....I don't like other people's dirt, either.
BUT....I also know that it's not a good idea to purchase new the first time. You never know if you will actually enjoy it, you don't know what you want until you experience a few night/weeks in a camper, being new doesn't necessarily mean that it's clean.
So, remind her that she: 1. eats in restaurants where you never know how clean the kitchen is, but she can clean a used one as easy as she can clean a new RV. 2. She uses public bathrooms and she can clean an RV bathroom to get it to her standards. 3. She probably stays in hotels where she sleeps in beds that others have slept in and they just "HOPEFULLY" changed the sheets. 4. You can always purchase a new mattress if that is a problem. 5. Purchasing a 3-4 year old RV will save you thousands in depreciation and it will probably retain it's original value from your purchase if you have made a mistake.
We have had 5 different RVs and have been into camping for more than 20 years. Our last fifth wheel was our first new one. I plan to have it for 10+ years or until our daughters are grown and gone.
2017 Ford F350 Crew Cab 6.7L 4x4 DRW