What I am about to say may upset some proponents of Elliott Waves, but the plain truth is Elliott-Waves used by themselves are allegedly of little value in actual trading. Next, ask the 5 traders to specifically define the number of waves they see on the chart. Use a Trading System, which does not rely exclusively on Elliott Waves and other subjective approaches. However, using Elliott Waves as part of a trading plan in conjunction with another time-tested methodology may work for you. Still another reason traders lose, many follow Time Cycles.
Cycles do in fact exist in the markets.
For example, Live Cattle may have a reliable long term cycle of 9 to 11-months, low to low. The problem is sometimes the cycles may come early or late, or skip a beat entirely. Shortly thereafter, the cycle bottoms and the expected move occurs . . . 4-bars into the NEW cycle, and at a higher price. This forces you out of the market because of the sudden loss, stop being hit, or lack of discipline, etc.