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 th...