How often should we take advantage of profitable spots
Here's the situation:
You're in the BB, action is folded to the button who opens for 3BB. You have a lot of hands on him and know he's doing that 40% of the time. You also know that if you 3bet up to 9BB his continuation range will be tight, let's say TT+, AQ+, or the top 5% of hands. That means he will fold to a 3bet 87.5% of the time there. From the BB, you only need him to fold 64% of the time for this to be immediately profitable, whatever you're holding. So great, you should 3bet with any 2, awesome.
Now here's the thing. You can't obviously do this all the time because even at the micros, people will catch on to it. So, my question is, when you have such players to your right, how often should you abuse them? What factors do you consider to decide this? I'm assuming you'll do it more often in the micros then in higher stakes, and more often against mass multi-tablers who'll probably take more time to notice (and by then they'll probably rather switch tables then having to deal with a constant 3beter to his left).
I could ask the same question for when we're out of position against a PF raiser who cbets all the time but will fold to a check-raise a high amount of the time. Again, profitable play, as long as you don't do it all the time. How often should you do it?