Current code requires smoke alarms in every sleeping room, outside each sleeping area, and on every level, interconnected so that one alarm sounding triggers all of them. Older Ocala homes typically have a single hallway unit, which is the arrangement interconnection exists to fix.
Alarms expire. The sensing element degrades and manufacturers date them for a ten year service life from the date of manufacture, not the date of installation. A detector that chirps and keeps chirping after a battery change has usually reached the end of it.
Carbon monoxide alarms are a separate device with separate placement rules and matter in homes with gas appliances, an attached garage, or a fireplace.
Technician insight
Check the date stamped on the back of the unit, not the battery. Ten years from manufacture is the replacement point regardless of how it is behaving.