I will admit, the first time I powered up my POVpoi, I was hesitant. The first time I plugged in the USB cable, I was hesitant, and the first time I plugged in a 12v charger, I was about to fill my pants. Did I do it right (first time I made a 1000 multiplier mistake), did I miss anything (forget two important pull downs), will I see smoke (yep, alligator clip scratched the mask and shorted VCC to GND.) BUT, none of those things compare to watching it all work flawlessly after a few revisions. It’s a matter of being aware of what might happen if you have potentially screwed up, and quick to disconnect things. I have not blown a battery yet, and I count my blessings on that because it’s fairly easy to do.
Oh, and if you are doing a custom design like I am, you have to be willing to spend R&D money. 
Right now every complete test cycle (all boards and components) is running me on average $250 …