Training the mind is essential in chess. You must instill all the mental habits that are necessary to ensure that you play at a consistent strength. One area for which training is needed is chess tactics. Chess tactics can be defined as sequences of forcing moves for which your opponent has only one or a few logical responses and any other legal moves will clearly be sub-optimal.
There is a risk that one might play a tactical sequence only to realize in the post-game analysis that there was a superior move order. Consider the following position:
You observe the pressure on f7 from the c4-bishop and the hanging rook on a8, which suggests that a tactical opportunity may exist. You assess 1. Bxf7+, Kxf7 2. Qd5+, Ke8 3. Qxa8 and see that you can win the a8-rook. Perhaps you see 1. Bxf7+, Kd8 as an option for your opponent, but you reason that you still win a pawn, and so you play 1. Bxf7+.
Here is where you should pause and ask if a transposition of the moves makes a difference before playing your move. What if you play 1. Qd5 first? 1. Qd5 is a double-attack, threatening both mate on f7 with 2. Qxf7 and threatening the rook on a8. Black cannot address both threats.
Best for black is 1. …, Qe3! 2. Qxa8, Qxc4. Here white has won the exchange (rook for a bishop) and his queen is misplaced. Is winning the exchange worth the loss of time? In this context, I think the answer is yes.
Train yourself to look at move transpositions when assessing tactics. This requires some effort. Select 100 chess tactics problems that have multiple-move sequences and practice assessing move transpositions after identifying and evaluating each tactic. This is essential – you must train your mind to do this every time a tactical opportunity arises.