It is always a good idea to buy a good quality paint brush. For the 2.5 inch Purdy brush costing around £12, these brushes seemed to be appropriate for all decorating jobs from oil based paints to water based emulsions. If you buy a cheap brush set you will be forever removing bristles from surface you are painting on. With these brushes there was hardly any bristle loss from the brushes. You don't have to spend huge amounts of money, however, in the long term the more expensive brushes will still be going strong (as long as they are cleaned out properly after each use) for years to come. I always buy my brushes from a DIY store and get them from the professional range of brushes. Some brushes unlike these, splay out after a couple of uses. These seemed to stay quite rigid, which is a good thing as it is better for cutting the paint around the edges of walls etc. Another problem with some brushes is that after cleaning them with water you get the water trapped in the ferrule (the metal bit of the brush that holds in the bristles). This was never a problem with the Purdy brush. Over all an excellent brush with great decorating results.