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

The oils are messy if spilt but the major issue is it will set of smoke detectors.

Vaping sets off smoke detectors...

The first property we had inspected is in great shape and we were asked to fix a handrail and replace a battery in a smoke detector( simple $150 charge for the inspection and $20 for me to fix).

@Deangelo MackMost cities will do a walkthrough inspection yearly to be sure it’s habitable and has smoke detectors and so fourth .

You put these info into your lease agreement - smoke detectors, pest control, crime watch - whatever in your state is required."

We don't really have a check list that we follow, however these are the things we look for when we do complete an inspection:- Smoke and Carbon detectors are operational- No apparent leaks when running faucets and toilets.

Electromagnetic Fields (EMF) are given  off  by electrical  devices.