Use synthetic brushes with wet products.
Synthetic brushes spread creams and liquids more efficiently because they won't absorb the product. They are also easier to clean.
Use natural bristles with dry products.
Natural bristles are more porous and pick up powder better than synthetic brushes. They also release powder to your face more evenly.
Replace old makeup sponges.
It's easier to replace makeup sponges and puffs than to wash them. Both deteriorate quickly after contact with water.