A question I have seen debated for some time across various hobby groups is around the best way to care for your brushes which makes absolute sense with a good quality kolinsky sable brush like a series 7 from Winsor & Newton costing c.£10 per brush. I have been using some of my existing series 7 for nearly a decade and do the following to keep them in good shape.
1) After each painting session apply brush soap - push the brush into the soap so that it goes into the ferrule. You dont need to apply too much pressure and dont worry if the bristles look fluffy! I use "The Masters" brush soap (mostly because I like the lemon fresh smell!)
2) This is the important part - run the brush into the crease of your hand, gently pushing back and forth at an angle close to the skin, this will gradually pull the paint out of the ferrule and bristles and clean the brush nicely. Once you are sure the paint has been worked out, gently roll the brush in the crease to form a point, wipe of the excess soap.
3) Put the dust cap back on the brush and store brush tip down - this is important as it allows the soap to keep working and any paint to fall down from the ferrule.