Painting thin lines with brushes.
Many people got problems painting thin lines with brushes and thus end up buying smaller brushes tend they need, IMO.
I blame the brush rather than the painter for this.
Most common available brushes sold for modelling don't hold a nice point, thus when painting or applying even slight pressure the bristles spread out in a fan pattern and thin lines cannot be painted.
The brushes I found the best for holding a good point are Japanese Calligraphy Brushes, I prefer Bunseido here as they are sold in most of the HS over here and are very affordable.
Another point about Calligraphy brushes , they bristles are bound together and fixed inside the handle without any glue thus making them long lasting as the glue won't be disolved by thinner, etc.
![Wink [;)]](/FSM/CS/emoticons/icon_smile_wink.gif)
Most of this Brushes come in a assortment of thicknesses for the handle, I found that a thicker handle allows better control of the brush strokes.
Natually good cleaning and care will ensure that they will produce a good result everytime.
FYI, I have some 0 & 00 Bunseido brushes that are still good after 6yrs of usage.