You may have just started painting and perhaps you don’t quite understand which brush you need. I will explain the factors involved in choosing the right paintbrushes:
Firstly consider which type of paint you are using, is it acrylics, oils or watercolour? If you are using acrylics or oils synthetic brushes are best, particularly if you are using solvents to wash or dilute oil paint. Natural bristles will erode very quickly and start falling out over time if you use them for acrylic or oil painting.
Watercolour and gouache are best used with natural fibre brushes. These natural fibre brushes are very soft and delicate on the paper. Sable brushes are the best natural fibre brushes and they are ideal for watercolours because they are so soft and smooth and they hold lots of water. There is now a synthetic sable brush available which is popular for watercolour and not quite as expensive as the natural stable brushes. I prefer the natural sable ones, but I have heard good things about the synthetic sable brushes. Sable brushes can be very expensive but they are a must for watercolour.
How do you spot the difference between natural and synthetic? Natural bristles are very soft and usually brown in colour, synthetic brushes are slightly more coarse with stronger bristles and they can come in a range of colours, white, orange or greyish brown tones. Most art shops label which brushes are to be used with what media so it is fairly easy to identify the brushes you need.
Brushes come in different handle sizes. The most important thing is to make sure you choose a handle length that is comfortable to you. Long handled brushes are traditionally used with oil painting but they are available for oil and acrylic painting now. Long handles can feel difficult to use for the beginner artist at first and they take a bit of getting used to. Long handled brushes are designed to be used with the easel so that there is a distance between you and your painting, so you can see the whole picture while painting. If your style is more detailed and you tend to create smaller work, a long handled brush won’t be for you.
Brushes come in all sizes, it is best to have a variety of different sized brushes so that you have more choice with painting. Even if you work really small I recommend having at least one large flat brush for backgrounds and coverage.
If you like detailed work then you can get a range of tiny brushes which will give you precise detail. Just be careful to look after the tiny brushes as they can get damaged in transportation. I like to use a plastic tube brush protector like the one shown below.
Advice for Beginners
I would advise those purchasing brushes for the first time to go to a shop and physically handle the brushes. Once you understand the different types of brushes you can then buy them online.
Also see my post The Four Most Useful Brushes for more advice on brushes.