Share When Do You Renew The Carbon Pads? By Carlyle Coash If you are using the carbon rubber pads to apply microcurrent stimulation for treatment anywhere on your body, we recommend you replace these pads once a year. The carbon pads are reusable, economic and very effective, but they do wear out. Trouble is, you cannot see when they wear out. Making a rubber electrode that will conduct electricity is a high-tech trick. When you run current, even microcurrents through these pads every day, the electrical quality of the material changes. The electrical resistance in the pads increases with use. Eventually, the pads act as insulators, not conductors. Replace the pads every year. If it suddenly seems that your unit is no longer putting out any current, replace the pads as this is likely the issue.