Part: Part Five - Betting Before the Flop

Set-mining in a multiway pot

Pre-flop
Blinds 100 / 200Pot 1,500 (7.5 BB)BTN3♣3♦● 25,000 (125 BB)YOUto actMP● 25,000 (125 BB)Openerraises 600 (3 BB)HJ● 25,000 (125 BB)Callercalls 600 (3 BB)SB● 25,000 (125 BB)posts 100 (0.5 BB)BB● 25,000 (125 BB)posts 200 (1 BB)D

A player opens to 600, another calls, and it's on you on the button with 3♣3♦.

An opener and a caller are already in; you hold 3♣3♦ on the button. Best?

WhyTwo players already in the pot is exactly the condition that makes a tiny pair worth playing: you flop a set about one time in eight, there are now two stacks to pay you off, and you have position to control the price. Three-betting only bloats a pot you're behind in; folding leaves a clearly profitable call on the table.
What happensBoth blinds step aside and you take a flop three-handed. The plan from here is simple: hit the set or be done with the hand.
Flop
Heads-upPot 2,100 (10.5 BB)A♠K♦7♣BTN3♣3♦● 25,000 (125 BB)YOUno set - just a small pairMP● 25,000 (125 BB)Openerbets 1,500 (7.5 BB)D

Flop A♠ K♦ 7♣ - you missed your set entirely. The opener bets into the field.

You whiffed the set on an ace-king flop and he bets. Best?

WhyAce-king-seven with pocket threes is a total whiff - no set, no draw, barely any equity against a bettor with a player still to act behind you. Set-mining only works if the release is automatic: no set, no hand, no hero-call to 'see one more.'
What happensYou fold and it costs nothing beyond the one bet you invested. Set-mining stays cheap precisely because most of the time it ends right here, on the flop.
You called for one reason - to flop a set with two players to pay it off - and released the instant the board bricked. The call and the fold are the same skill; the discipline to let go is what makes the mine profitable.

Small pairs earn their keep by flopping sets - more opponents mean more implied odds and more stacks to win, but only if you'll fold the times the set doesn't come.