As long as the washing and care instructions are followed correctly, the sheet should have no problem lasting up to three years or more. Sweat and natural skin oils can sometimes tarnish the silver over time, reducing the conductivity. However, much of this can be prevented by fitting the Earthing sheet underneath your current bed sheet or by washing regularly, just as you would a normal cotton sheet. Washing strips body sweat and natural skin oils from the silver and keeps it conductive.