The electrode pads adhere to the body via the hydrogel area (similar to hospital EKG electrodes). Our electrodes have a long usage life of about 20-30+ applications. To maximize electrode pad life, make sure your skin is clean and does not contain any lotion before applying the pad. Tip if gel pad adhesive if it’s no longer sticky- Using a wet towel or cloth; Gently clean the hydrogel area of the electrode pad and allowing it to air dry for a minute will help restore pad adhesiveness and maximize usage life. Other factors that affect electrode pad life expectancy are your skin type, oils, and pH levels. When a replacement is needed, please purchase electrode pads by clicking here.