Separate the goal from the price tag

A combination must be judged by what the total of subtasks accomplishes.This means that worrying about the price tag of an isolated subtask will only distract you. 

White to move

r3rk2/2pb3Q/2q2bp1/2n1p3/1pP1P3/1B2RN1P/P4PP1/3R2K1 w - - 0 31

Salgado Lopez, I. vs. Granda Zuniga, J. Quito 2012

Chessable 1001 Chess Exercises for Advanced Club Players.

White has sacrificed a bishop for two pawns and an attack

• 31.Nh4 Bxh4
• 32.Rf3+ Bf6

What has white accomplished, and what has been the price tag?

Goal:

clear the f-file for the rook

Price tag:

a knight

Means:

Nh4 threatens mate in 1

Rf3+ is with check

Rf3 pins the bishop

The point is, that the moves are measured in time. As long as you gain time, there is no need to evaluate the price tag of the individual subtasks.

Follow up

• 33. Rxd7 an exchange sacrifice. Threatening mate in 1
• 33. ... Nxd7
• 35 c5 opening another LoA (line of attack). Threatening mate in 1

Goal:
opening a LoA

Price tag:
An exchange

Means:
Rxd7 threatens mate in 1
c5 threatens mate in 1

Notice how the defending pieces become clumsy. There are too many potential invasion squares to defend.

Notice how white is only interested in the LoAs and ignores worries about the price tag.

That is what we need to learn:
look at the goals
treat the means as just means
manipulate the time to accomplish a goal

don't let worries about the price tags of subtasks cloud your vision.