Dentist recommends changing out your toothbrush every 3 months. After normal wear and tear your bristles start to get worn out creating a less effective toothbrush. Clinical studies show that a worn out toothbrush removes less plaque than a new toothbrush. Your toothbrush builds up a large number of bacteria, so common sense practices also suggests to replace your toothbrush every 3 months. It is also a good idea to replace your toothbrush after getting over a illness. Keep the earth green Almost 50 million pounds of plastic toothbrushes make it to our landfills every year. All that plastic can take up to 1,000 years to decompose and can even leak pollutants into the surrounding soil and water. WHY We Use Bamboo to make Toothbrush Bamboo is environmentally friendly because it grows super fast, over a yard per day that's over 3 feet every single day, plus bamboo can grow in close proximity to each other.