I'm at this point I think. I've been using the same Ross brushes I got in the master paint kit 3 years ago. The fan brushes have long been destroyed. I'm hesitant to get others because these are 'functional' but it's really difficult to, say, use a two inch brush to create soft grassy areas as a lot of the hairs have split.
The way I see it - I could purchase new ones, take care of them better now that my knowledge is enhanced, and definitely keep the older brushes rather than tossing them in the trash. I can see those brushes being helpful for applying liquid white and clear, scrubbing hard, and other activities that can wear a brush down. That way, you can keep the newer brushes more pristine for a longer period of time by using them for delicate details.