How Far Does Calculation Go?

that assumes i make it past the opening phase...

Richard Reti was asked how many moves he usually calculated ahead, and he answered "As a rule, not a single one."

This is why you look for candidate moves.  Generally 3.  You then calculate them out as far as you can.

Forcing lines are easier since they are...well...forcing lines.

I create pattern and if i feel it is the right moment i start to calculate. Because if their is no pattern, then their is no combination. 

My opponent at my level don't know how to create pattern. So,  i don't need to worry about their combination. If they have any,  i would like to fall on their game plan to see what they have. 

Like pushwood says it just depends.

Not only the current position, but if there are no future tactics about to happen, then sometimes you don't calculate at all. Instead your energy is spent on trying to form the right evaluation of the position. Who is better, why, where the pieces belong, what the right plan is, that sort of thing.

Deep precise calculation is a must when, on the board, there's piece activity involving forced play and is carried out until the player is (more or less) confident in his evaluation of the resulting positions.

Contrary to popular opinion, there are very few situations not demanding precise calculation. What varies is the extension and depth (the number of branches and length of the variations). For example, if both players have free passed pawns in a minor piece ending, the variations will likely be about who reaches the 8th rank first, the methods to delay the opponents' advance and to speed up the own. In a mutual attack against the Kings on opposite sides of the board, the variations will probably be devoted to increasing the strength of the own threats as to enforce concessions from the rival (material, weakening his own position, or even a single tempo). But even in a calm situation with no complicated active threats, going deep into the position helps to uncover simple tactics that may win a tempo or disturb the opponents' piece and pawn coordination.

What is a simple move?

calculation is deep enough until you define is the outcome good for you or not + 1 move.

so if f.e. after 4 moves you do not like what you see, go to next line, if you like the outcome than 1move extra to see what your oponents possibilities are

Jedan potez

Uh oh.   #10 is the answer.  

If the move is a checkmate, then anything else is unnecessary. Otherwise...

Take this case: I had a no–Queens middlegame position in a game where my central pawns needed support to become a real threat. The better piece to do it was the King moving Ke8–e7–f6–e5, but being a middlegame it was possible the existence of hidden threats along the road. I had 0-0 at hand, a waiting move to check things out before moving the King into the center with Kg8–g7–f6–e5, but that meant an extra tempo from the King and another from the misplaced Rook in f8. Therefore I had to calculate in order to know if I could save two tempos.

The thing is that in order to win games you'll likely need to invade the enemy position to create threats, but as you move your pieces forward they may expose your rear to potential threats, so even if you want to win "peacefully" by strategic and positional means, there's still the need to consider the not–so–peaceful tactical schemes from the rival as you progress inside his camp.