Stained is Not the Same as Unwashed

"I've started painting using acrylics, I've been practicing painting skies and the tip of the brush is faint blue, does this matter?" -- Ash

Short 'n sweet: no.

Well, actually, not that sweet because having a staining pigment transform the hairs on a brand-new brush from pristine to stained in one painting session isn't sweet. I know, I know... a brush is merely a tool and it's there to be used. Pointless not using it...

See Also:
• Parts of an Artist's Brush
• How Many Brushes Should You Use in a Painting?

^{Image: © Marion Boddy-Evans. Licensed to About.com, Inc}