Smells fishy. your thoughts? 

Do I have recourse or as you suggested, it'd be an uphill battle?

This is not only pain when it comes time for utility bill reconciliation but also can have adverse smells from the oil tanks in the basement.

Let the great cashflow vs appreciation battle begin...My opinion is to define your goals first.

If you are doing the work yourself then be ready every time a guest cant get in, propane has to be refilled, extra sheets were needed and cant be found, they had a dog that you didn't know about and there is hair everywhere and you have a guest checking in, they smoked weed or cigarettes in the home and you cant get the smell out, the sewer backs up, the dishwasher breaks................ good times friends!!

As a Real Estate Development, I have primarily focused on construction; managing construction budgets, dealing with contractors, and fighting the battles no one else wants to battle. 

Pick you battles....... is it worth the hassle over letting them walk 3 months early?

But the battle continues.

Soooooo...at least it isn't Summer but...The smell, which I have been blaming my dogs for...has actually been linked to a fairly big, unpleasant error. 

It can be a very difficult up hill battle as they were likely not educated on finances growing up.