A boar bristle shaving brush will last for several years if it is cared for properly.
A boar bristle shaving brush will last for several years if it is cared for properly. A badger shaving brush should last at least ten to fifteen years.
Do Shaving Brushes Wear Out?
It can take a long time for the hairs on a shaving brush to wear down. The hairs might not be strong enough to use the brush effectively and whip up a lather. 
How Long Should A Badger Brush Last?
It lathers well and is soft, so badger hair is often preferred for wet shaving. Ensuring that badger brushes last a long time is important. A badger shaving brush should last at least ten to fifteen years. 
How Long Do Shaving Brushes Last?
Keeping in mind that there are a number of factors involved, even as a conservative estimate, 10 years is a pretty reasonable and typical lifespan of a quality shaving brush. 
Should You Rinse Your Shaving Brush?
After every shave, rinse the brush. The brush should be given a deeper clean once a month. It doesn’t have to be fancy, just your regular hair wash and warm water. The residual lather from the bristles and knot will be removed with this. 
Frank Harmenstein is the lead editor of the grooming website Cut Throat Straight Razor, and has over 15 years of experience in the industry. He’s personally tested and reviewed over 200 different straight razors, and has written countless articles on the subject.