As a trader we deal in probabilities. Market breadth is very good at signalling probable correction zones ahead of time. That way you can reduce risk aggressively or position for a turn.
The Stockbee Market Monitor is one of the ways to use breadth to time markets. There are many ways in which you can do it once you understand the concept of market breadth.
One of the best and probably only book on market breadth is The Complete Guide to Market Breadth Indicators: How to Analyze and Evaluate market Direction and Strength (Hardcover) by Gregory L. Morris. It is the most comprehensive collection of breadth indicators and studies.
Breadth indicators can help you avoid big drawdowns and are objective ways to find market strength and weakness.
As you can see as soon as Market Breadth became extremely positive, the market entered a correction phase. Extremely positive breadth tends to result in selling in short time frames.