We have been using Dexcom for about two months. Generally we have gotten away without taping the transmitter down - sometimes when it was looking like the tape was peeling up, we put an IV300) on it, but that did not last. It seems like Opsite Flexifix works for most people who want to tape it down. Question - do you use a 2 inch or 4 inch roll? And do you tape it down as soon as you insert it? Does that last for 1+ weeks or do you wait until it starts to peel up? Just trying to figure out which kind to order. Thanks!