Chess is a thinking game. Thought processes and time management are intertwined and are two of the most important skills.

I break down time management into two sub-skills:

• Macro Time Management: The ability to use almost all of your time every game without getting into unnecessary time trouble.

• Micro Time Management: The ability to allocate more time to the moves which require more thought.

Micro Time Management can broken down further into two parts:

• The clock situation, which includes how much time you have remaining on your clock, and, if there is a non-sudden death time control (e.g. 40 moves in 90 minutes), the current move number (and thus how many moves are left in the time control).

• The position on the board with respect to how much time the current move deserves. This latter aspect of Micro Time Management can be called the Criticality Assessment.

Usually a critical position calls for extra care and extra time. What can be considered a critical position? Let's start with a list provided by GM Lev Alburt and Al Lawrence in their book "Chess Rules of Thumb."

Rule of Thumb #135 is

"Recognize five characteristics of a critical position:

1. When the game changes from known theory into unknown territory, from opening to middlegame, or from middlegame to endgame.

2. When any pieces are exchanged, especially queens.

3. When there is any change, or possible change in the pawn structure—especially in the center.

4. When you have a tactical (short-lived) advantage which will disappear if not exploited now.

5. When you see a move which seems to win."

Their very next Rule of Thumb, #136, is:

"A critical position is one about which you should think long and hard."

This is all good stuff, and I would like to add more on the subject.

A critical position is one where if the best move(s) are not chosen, then the likely outcome of the game is affected.