Most sponges should be cleaned at least once a week using gentle baby shampoo. If you have acne-prone skin, wash 'em everyday. The sponges that come with your powder foundation should also be cleaned weekly and replaced once a month (or when the sponge begins to lose its firmness or to crack). The truth is, your basic drugstore wedge sponge is really only meant for single or one-week use.
Sandy recommends the beautyblender sponge, which comes with its own cleanser or can be laundered in a garment bag in your washing machine (but not the dryer) and boasts a shelf life of three to six months! Also try: Quo wedge sponge, at Shoppers Drug Mart; M.A.C. disc sponge.
Mascara has the shortest life span of all and should be replaced every three to four months—six at the max! But when its time's up, all is not lost: You can actually reuse the mascara wand as an eyebrow brush. Simply wash it in warm, soapy water with a face cloth and lay flat to dry overnight.
Powder generally has a long life and can last anywhere from six months to one-and-a-half years, depending on how well you take care of it. (Sandy's personal fave? M.A.C. Studio Fix Powder Plus foundation.) To prevent oil buildup: Store the sponge in its proper place so that it never sits on top of the powder and spray it after each use with a cosmetic sanitizer like BeautySoClean Cosmetic Sanitizer Mist.
The curler hardware itself can last a very long time. However, the effectiveness of the tool depends on the condition of the pads, which need to be replaced every two to three months. You should also clean your curler once a week with rubbing alcohol and a cotton ball to remove any makeup buildup and/or bacteria. Sandy suggests the tried-and-true Tweezerman Classic lash curler and refill pads.
While you're cleaning house, why not freshen your makeup bag as well? Sandy loves the Helly Kitty Noir collection, available at Sephora.