do I need a running vest for my phone

A zipped trouser pocket, waist belt, armband or chest vest can all work for different runners. Think about phone access, movement, clothing and whether the device feels secure.

The Défi design carries the phone in a zipped 20 × 13cm chest pocket, with two smaller zipped shoulder pockets. Measure the phone and case before deciding whether the layout suits you.

Try the loaded carrier on a short route and check comfort, movement and access. If your current setup already works, there may be no need to add another piece of kit.