As of February 1, 2011 carbon monoxide detectors are required on all levels (including basement and finished attics) of one and two family homes in Wisconsin.
Smoke detectors are also required on every level of one and two family homes.

Test Monthly

Remember, a detector that is not working cannot protect you. Follow the manufacturer's instructions to test them monthly.

Clean your detectors using a vacuum cleaner, without removing the detector's cover. Dust and cobwebs can reduce a smoke detector's sensitivity to smoke.

Never paint a smoke or carbon monoxide detector.

Smoke / carbon monoxide detectors do not last forever. You should replace detectors that are more than 10 years old.

Change Batteries Annually

Tragically, many fire deaths happen in homes as a result of malfunctioning smoke detectors that have batteries that are either worn out or missing.

Change your batteries at least once a year. Test (or simply change) the batteries every time daylight savings comes around in the spring and the fall.

While many battery powered units "chirp" or give some other audible signal when their batteries need replacement, do not let it come to that.  Change them often!