Value 3-bets only against early opens; the interesting hands flat in position.
The reference tier. 3-bets are linear and value-heavy, live-style; calls are pairs, strong suited hands, and the best broadways.
Good position against a strong range. Flatting dominates: you keep their dominated hands in and your speculative hands cheap.
Assumes a ~4bb open; 3-bet to ~3x the open in position, ~4x from the blinds — larger as stacks deepen.