I used to wear mine on my bicep, opposite arm from my watch. In almost 4 years of use, I never had connection issues running (with Garmin 920XT) or biking (Edge 520). For races short of IM I wore it the entire race, turning it on just before swim start (for IM I used a chest strap).

I have stopped using the Scosche since getting a watch with integrated HRM, since it is one less device to put on, clean, and charge. I was also starting to have issues charging the Scosche, which I put up to worn contacts after ~1000 workouts.