Not all hairbrushes are created equally. Some can last years. Others will wear out in a few a months. Hair stylist Robert Steinken recommends that hairbrushes be replaced when the bristles get soft or burned. Bristles that are worn can be potentially damaging to your hair cuticles. You're not doing your hair any favors if you're stubbornly holding onto an old brush for the sake of the environment.
Your best bet would be to buy the sturdiest hairbrush available. Use it until the caps on the wires break off or the bristles get worn down, then replace it with another sturdy brush. Keep in mind that everyone's hair is different, you'll have to find the eco-friendly method of hairbrush conservation that works for your hair and your brush.
Don't toss those old hair brushes. Even though they might not work for your hair and scalp anymore, they still have a lot of life left in them. Here are some ways to put those old hair brushes to work.
1. Put an old brush out in the shed. Use it to clean muddy gardening tools before you put them away.
2. Put one in the garage. Use it to clean mud off your tires.
3. Put one in the antechamber or mud porch, use the brush to clean off your shoes.
4. Use as an implement to remove cockleburs from your dog.
5. The hair brush can be used to dust off muddy sports equipment.
6. Write your own in the comments.