To minimize bacteria growth and keep your makeup brushes alive for longer, you should clean them about once a week. Instead of paying $32 for a makeup brush cleaning mat, use a paper plate and hot glue to get (basically) the same results.
A simple, natural, and affordable makeup brush cleaner! This brush cleaner can be used daily or weekly to clean makeup brushes and break the cycle of bacteria and breakouts. http://livesimply.me/2015/06/21/homemade-natural-makeup-brush-cleaner/