It is considered to safely use makeup brushes by replacing them every three months. The obvious signs that your makeup brushes need replacement are by looking at their color and shape even after cleaning them. If it still looks disorderly and stiff, it may not be able to do its job anymore. You can also notice if your brushes are starting to look bristled and it is starting to fall off. We prefer that you replace them as this can damage the way you put your best makeup on!