You are playing defense using this approach. 

There is another aspect and that is the defense of claims.

A renters insurance policy is not designed to handle this type of “co-mingled” defense and remuneration.If the resident caused a fire, the owner could potentially be prohibited from tendering a claim against the renters policy for the liability to pay for the damage.

(Source: Portland Urgent Care - and about every allergen and sinus clinic in the country).Your failure to manage to the lease after knowing that there was a cat on the premises could prove to be a defense should you offset the security deposit without having receipts from credible/industry trades with their findings noted. 

You're closed minded and not willing to admit the benefits of something that clearly has some, because you're defensive and don't want to admit that everything is not all about math and better / worse.

In the closing attorney's defense I should have been more vigilant at closing as far as how the deed was written...

IIn most states as long as the tenant is 1% liable for the claim his insurance will take care of the defense costs and pay claims up to his limit. 

Though, there are usually hoops a tenant must jump though in order to do this in a defensible manner.In states that allow this it this, it often takes the form of:The heater (or whatever) goes out and the landlord isn't addressing the issue in a timely manner.The tenant gets fed up, and fixes it himself (or hires it out) and then deducts that amount plus incidentals from his rent.Then the tenant writes a letter to the landlord explaining that he's deducted from rent and why he has done so. 

Her defense is that someone else promised to pay for it? 

In my defense, you should have seen what I originally wrote before judicious use of the Delete key.I guess it'd be one thing if I said "I am a lawyer and this is legal advice.