According to this document, the law for habitability in Illinois says:“the defect must be of such a substantial nature as to render the premises unsafe or unsanitary, and thus unfit for occupancy."

I remember many years back when I was signing a rental lease; the landlord had a sheet where I noted the all the defects that already existed on the property like scratches on the kitchen cabinets, door slightly chipped etc.

Defective service is frequently used as the basis for a TCB challenge. 

However, I would generally say that any major defect that was not disclosed or found during the inspection period, it is reasonable to request remedies.

More often than not, lawn mower injuries are caused by improper use or user error rather than a product defect.

And if you have already promised and signed off a new lease with a move in date of that same day, you paint yourself into a corner unless the new tenant accepts those pre-existing defects in order to move in early.

For the toilet to move one of the connections failed due to an initial installation defect or rust/deterioration.

Last one was that the bath tub was "defective". 

It turned out to be a defective septic pump it would run for a few hours then turn off then run then turn off.

@Tchaka Owen  Yes, our standard contract does state that brokerage fee is paid at closing by a separate agreement, so buyer should always be made aware before signing an offer that they cannot "demand" that broker receive less, that commission is a negotiation between seller and broker, not them, but if I feel it's worth it (like reduced buyer pool due to poor location or defects and offer is solid), I'll request consideration from my broker to help my seller sell.