When to complete these hands in the SB

When and under which circumstances do you complete hands like K6s,K5s,K7o,Q3s,Q4s?

I have also trouble when to bluffbet those hands let´s say in a three-way pot on boards like A73 or K92.
How often do both need to fold for me to make the bluff profitable?

[yourface]

do an EV calculation to figure out how often you need villains to fold.

0 < (money in pot)*(probability of villains folding) - (cost of bet)*(probability of villains not folding)