How long should I wear silicone sheets to where they are still effective?

Dear julieshane35,
I understand you are concerned with the appearance of your scars. As your scars heal, it should flatten out and lighten. Loss of pigmentation or hyperpigmentation may also be experienced but will resolve over time. Always follow your surgeon's post operative care instructions when it comes to scar management to avoid any complications like infection and for faster healing and recovery. I recommend my patients to use silicone scar gel for 3 months. 
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Dear julieshane35,Most surgeons recommend 2-3 months although scar remodeling occurs up to 1 year, so some recommend longer. Your surgeon should have a recommendation based on his/her experience.Best regards,Nirmal R. Nathan, M.D.Certified, American Board of Plastic SurgeryMember, American Society of Plastic Surgeons