Hi Mudcat,
IMO, if a pattern is correctly identified (not always the case), when it breaks, it is either completed or negated, but its influence on the chart does not end there. Look at how the lower trendline of an ascending triangle will often extend far beyond the formation itself to become support on the subsequent price rise.
Looking back over the chart, does a particular pattern repeatedly form and, if so, how did it, and other patterns that formed, play out in the past? This will give us clues as to that stock's "personality" and how it will trade in future! As to how relevant a failed H&S Top that occurred two years ago is today, IMO everything on the chart helps, but I would certainly put more weight on subsequent, more recent, patterns.
Chart reading is a combination of art and science, Mudcat, and reading this board you have probably noticed that more often than not even the best traders here disagree as to future direction. While giving consideration to the opinions of others, it is YOUR money on the line, and, therefore, ultimately, it is only YOUR opinion that counts.
N2B
Market Data 
Markets 
AI
