NL25 - Double barrelling - In what situations? With what frequency?

[automaton_22]

Hi all.
It has come to my attention that I often get into trouble double barreling.
My raise gets called pre-flop, I make a c-bet, the c-bet gets called.
With what frequency am I firing a second barrel on the turn?
Do we ever second barrel light?

How strong a hand do we need to fire?

Should I use this move very rarely? Or?

I know this is very much in the abstract, but would like an indication about how often it is profitable to second barrel, and in what situations.

Example hands would be great.