I will keep this simple ;
The paint brush has evolved over the years .From what the bristles were made of to how they were fastened to handles . Some folks think the Brushes with synthetic bristles are the cat’s meow ! I say B.S. !
Having been both a sign painter and detail painter for many a side buck ( No, I never did these things as regular jobs )I learned about Brushes .This even extends to painting boats and houses !
The brush is a tool .Not a toy ! They can be cheap or very expensive ! That’s a fact ! They come in many shapes that I won’t cover here . they have all kinds of bristle material too . These are my recommendations though .
Tiny ? Four 0 or such for details Bristles ? Mink or Sable hair . Cost High !
Medium ? Round Sable or Camel hair in a size you need .
Large , Well , I like these in flats from 1/4 inch wide to over 3/4 of an inch .
main and most important rule Keep them surgically clean ! Don’t let them sit in water or thinner till they take a curved set ! Clean by Blotting and then shaping to original profile and standing in a can or jar with the bristles up .
You can assure the shape by drying them with a little spit or water when you shape them then leave them alone .Next time you use one it will be ready for you . Good painting T.B. My comment about the life of brushes can be understood better by this .I have six brushes I bought forty five years ago to paint a friend’s house inside . The brushes are still here, clean and well shaped and in like new condition .