If you're using hair brushes (no-synthetic) it's good, once in a while, put some hair conditioner on them - it won't restore the natural oils from the fiber, but it'll make softer and plush *like human hair would*.
Other tips : don't put your brushes to dry with the point facing upwards - the water will enter the ferrule and the brush will spoil earlier, because of fungus or the glue softening up. The best way is to dry either laying down, or using this:
It's a brush washer - you hold them on the spiral, and the water drips on the cup. You can find on art stores (or online - i found this pic at
Art Supplies at Cheap Joe's Art Stuff)