Many silicone forms have two year warranties, and you should be able to get at least that much life out of one. Be sure to inspect your forms regularly for any defects that might develop within the warranty period. Silicone forms may split their outer envelope seams, wrinkle or develop internal bubbles, while fiberfilled or foam forms may change their shape, decay, crease or become compressed. Most insurance companies (this can vary) subsidize the purchase of one breast form per year and two mastectomy bras every six months for those who have had breast cancer surgery. "Casual" wearers (not full daily use) should be able to get longer form life spans than this; possibly as much as 5 years if the silicone does not harden or break down. The time involved is dependent again on how much the form is worn.