And for reference, public housing in the US doesn't have a very good reputation. It's not just the poverty of the residents, it's the management, too. A survey of headlines about the NYC Housing Authority (NYCHA) will find problems with lead paint that the agency tried to cover up, issues with toxic mold, falsified maintenance records, energy-efficiency projects which change out the light bulbs in the apartment for LEDs at a cost of $2000 a bulb, and workers who just sleep on the job — which is in fact a step up from the workers who made headlines about having orgies on the job (no, seriously.)

It comes down to the tenants not being the customer. The customer is the government. And as long as they're paying, you do the least possible to maintain that.

If the government standard says you need to do maintenance on HVAC once every 6 months. You do maintenance once every 6 months, regardless of whether or not it needs it more often.