Probably if you are new to forex market you will ask this question. May be you think that the human brain can process the chart information better and make better forex analizys and decisions about the possible market directions. Well... you are wrong. The forex market is unpredictable as the most things in our lives. If the market becomes predictable, it will stop existing. Then what can we do? We can monitor and find specific market situations after which something is happening. Of course you will never find such case in where after A follows B in 100% probability. But you can find a 60% one. And this will lead to developing forex trading strategy and when the strategy is crystal clear, it can be coded into expert advisor.

There are several reasons for that. First of all the robot never sleeps. It can be online 24/7 and wait to open a trade or manage already opened trades. It can execute many trading actions in miliseconds if needed. The expert advisor has no emotions and doesnt panic. No matter what happens on the market it will stick strictly on its trading logic. And may be the most important of all - you can backtest it. You will know exactly how this automated forex strategy was doing in the past. What was the maximum drawdown, what was the maximum consecutive wins or losess and so on. By this you know what to expect and you will notice if there is a difference between the current trading results and those in the past. You can have unlimited amount of expert advisors.

As everything around us, the markets change too.The swaps change. Economic results change. Market volumes change.Trends are becoming bigger or smaller, ranges are becoming wider or thiner. The forex expert advisor is designed to work within some specific market parameters. When they change beyond certain limit , the EA will stop working as expected.Usually this doesn't happen right away but like a process of constantly getting less and less profits.

There are many types of trading systems and many lifecycle models but the one we choose has test, out of sample test and trade. The test is the largest period where we test our rules. It must be big enough in order to get enough trades for good stats and not so big, because as we said in the previous pharagraph -it can be close to its end or have bad backtest results just because we are including different market conditions. For example 10-15 years ago we had 5-8 points spread on EURUSD,now we have 0.8. If we test on such old data we will have good results wich are not real. We have chosen that backtest period to be close to 2 years. The next important period is the out of sample test. In this test we verify that the system still have the same performance parameters as in the test period. If the system can pass that period it is ready for trading. In the most common case we have 2 years backtest, 6 months out of sample test and 1 year trading.