This business of adjusting to the ante structure

[Micturition Man]

Ante structure is critically important in determining optimal 3rd street play.

Ante structure determines the starting pot size.

Starting pot size determines the value of your steal equity.

Unless you have a hand that is a clear favorite to the board, the EV of folding versus limping versus completing
is a function of reverse implied odds and steal equity. (If you have a draw the decision is a function of implied odds versus steal equity.)

In other words, ante structure is the critical factor in determing how to play any kind of mediocre hand in a stud game.

To be more specific here are three common scenarios:

1. When you have a hand that is mediocre relative to the board.

If you have something like (5s4s)4c and there are three overcards behind you, your decision between folding, limping or completing is purely a function of pot size (obviously I am holding the exposed cards constant and assuming generic solid opponents).

With a small ante structure you should definitely just fold. With something like a 30-60 structure you might want to limp.

With a Bellagio 300-600 structure, where you will be getting 7:3 or 2.33:1 you have no choice but to complete.

2. When you have total garbage but a scarecard in the door.

Same scenario as above but you have (7s2c)Ad, four cards remaining behind you, and no aces exposed.

Again you should fold in a small or moderate ante game, imo. In a Bellagio 300-600 structure game you may have to complete purely for your steal equity.

3. When you are facing someone in any kind of semi-steal position and you would be incorrect to play versus the holding they are 'representing'.

Say you have (45)4 and a T raises into you, a J, and a deuce bring-in.

Because the T's distribution should be greatly influenced by the ante structure in small ante game you fold without hesitation. In 30-60 you probably still fold. In the 200-400 again you are probably forced to play.

Note that I have not even mentioned the effect of the increased pot size on 4th and beyond.