If the gel pads are not sticking to your back effectively, you should replace them. The timing will vary by person, depending on factors like skin type, activity level and how long you leave it on your back. For your safety and proper functioning, only use gel pads recommended by the manufacturer. To learn about compatible gel pads and where to buy, please contact consumer relations at 1-(800) 395-0689 or click here. No other method should be used to attach the Aleve Direct Therapy device to your back.