For the most hygienic and effective cleaning, experts recommend starting fresh every three to four months or when you notice the bristles becoming frayed. If you’re keen to cut down on waste, consider Quip (from $25; getquip.com), a service that mails you a fresh head to pop onto the same handle every three months.
The synthetic mesh you use to get your body clean can also be a breeding ground for bacteria. Hanging it to drip-dry will help, but you’ll still want to swap in a fresh one every two months.
Microbiologists have found that kitchen sponges can harbor 82 billion bacteria per cubic inch—and the strongest bugs survived even after the sponge was microwaved. Toss and replace every one to two weeks.
This article was taken from:https://www.realsimple.com/home-organizing/cleaning/cleaning-more-rooms/replacing-your-products