My best pure badger brush has seen a lot of action and it is still in tip top shape and looks and feels clean. I bought it new and it gets enough cleaning with my shaving soaps and pre-shave soap oil when lathering and being rinsed.

So the conclusion is that no new conditioning is needed for this brush.

However, I did once see an old badger brush that looked like it lost some of its Mojo hanging around 20+ years doing nothing. Perhaps a weekly shampoo and conditioner may have been the ticket to breath life back into that brush.

Pabster