To be fair, this is a tip that works better when working with a number of steaks over a period of time as opposed to single steaks. It still works, but just keep in a mind that it is an inexact science. Fat content (or type/cut of meat), thickness of meat, and heat source are all variables that change how long it takes to cook a given piece of meat. If you haven't eaten steak, I'm guessing you haven't cooked a ton of beef, so allow me to step outside of the scope of this post and suggest a great cookbook: How to Cook Meat
How To Cook Meat by Chris Schlesinger & John Willoughby. Chris Schlesinger runs the East Coast Grill in Cambridge, MA, of Hell Night fame.
One of my favorite books, mine is falling apart from use. 75% grilling but other techniques are used as well, and the four main categories (beef, pork, veal, lamb) are covered. Lots of instruction and useful info aside from the recipes, which are delicious. Buy it buy it buy it.