Ever forget to bring a usb cable or you brought the cable but it has the wrong connectors on it. The results is the same, you can’t charge your gear.
Here is a cable I found for under $10.00 that has it all. Iphone 3/4 Iphone 5/6 lightning cable, a Mini USB for your gopro and 2 micro usb for Android and everything else.
Here is an Amazon Link: