> Both my coworker and I had AC issues. For him, he called his landlord and that was it in terms of hassle. He then went after his landlord for a rent reduction due to the AC being an issue for a week.

This is the best case outcome. All too often, especially with mom and pop small landlords, the repairs are delayed or done incompetently, or there is no local ordinance offering recompense to the renter, or both.