TENS is non-addictive. This means you can safely use your TENS as often as you like without fear of nasty side-effects. A successful approach can be to use your TENS machine as a replacement for analgesic drug-therapy. Rather than reaching for a tablet, reach for your TENS instead. TENS can provide relief for many hours. If you know that your pain will last for about 4 hours, try using your machine around the 3 1/2 or 4 hour mark to pre-empt the onset of your pain.