Also, it's imperative to check all plumbing and electrical, including smoke/CO detectors.  

Due to the extended list of improper and outdated wiring mentioned in #10, we need an exact quote on how much it will cost to repair all electrical issues throughout the premises.6-Must install all appropriate carbon monoxide/smoke detectors as needed all throughout the living area space; including basement, stairwells and other living areas. 

@Matt Gilroy Tell him your doing a random check to look at smoke detectors, check furnance, and general inspection of property for your records.

I replace old smoke detectors with the 10 year lithium battery ones that are built in. 

I have smoke detectors there too .

I think the only big thing that we'll need to address is smoke/CO detectors. 

I put in my lease that I will be replacing the furnace filter, batteries for smoke detector/CO detector, and inspecting the unit every 6 months.

I also install fire detectors, flood sensors, and carbon monoxide sensors all linked to the alarm system to provide additional protection for my property, tenants, and myself. 

What special rules do I need to follow (e.g. proper number and placement of smoke detectors and carbon monoxide detectors) that might apply to a rental property that don't apply to a primary residence, or where can I find these rules?

All that aside Home Depot sells 10 year built in lithium powered smoke detectors for 24$ where the battery is not removable and put it up as high as possible screw it directly into the wall instead of a spin off plate so it can’t be easily taken down