Caring for your brushes and other equipment will ensure they last a long time.
I prefer a number 5 synthetic pointer brush for fabric painting with pencils, but feel free to experiment with what you have and use the one you feel does what you want.
A few simple hints…
NEVER leave your brush sitting in water.
ALWAYS clean brushes after use, never leave product to dry on the brush.
Lay brushes FLAT to dry.
Every so often give the brush a good wash.
Wet the bristles and rub lightly on a cake of soap, cup your hand and swirl bristles gently in the palm.
Then give the brush a good rinse in clean cold water.
Dry the handle and ferrule with a towel or tissue and gently pinch/squeeze the bristles in your fingers, reshape bristles to a point and lay FLAT to dry.
When dry brush can be stored handle down in a jar or pencil holder. NEVER leave or store brushes bristle down.
Look after your brushes and they will do a good job for you for a long time.
Brushes are like shoes, buy the best you can afford and remember expensive does not always mean the best for the job.