Smoke/carbon monoxide detectors and their batteries
As per the U.S. Fire Administration, the rule of thumb is to typically replace the entire smoke or CO alarm by the date of manufacture printed on the alarm itself. Test the alarm every single month and replace batteries twice a year, at least. You need to throw out these 30 things ASAP.
Dental company Oral-B recommends replacing your toothbrush every three months. If you notice the bristles are frayed, replace it sooner. It’s also a good idea to replace your toothbrush after you’re sick to avoid spreading germs to fellow toothbrushes nearby.