It's a statistic fact that a major of forex robots sold online fail and tend to lose people money, but if you want to find one that will make you profit and save you time and energy at the same time then there are a few things you need to consider.
Many vendors claim huge successes and results with their robots with little to no loses, but this is not realistic, literally. The results they give you are usually just backtests which are not based on real results but rather hypothetical situations that are just simulations of the market, not real data that will actually help you. If vendors provided real data then their products would not look nearly as appealing.
The hypothetical simulated results have limitations and do not represent real trading and will not help you much at all. Backtests which is what most sellers use can not predict future results or profits, they are created simply to make their product look too good to be true, and they are usually. There are plenty of good forex robots out there, you just need to be patient and be willing to wade through a sea of worthless forex robots.
You can usually tell if a robot is good if the results are truthful. They may not be perfect and there may be some loss involved, but it will be realistic and give you results and projections you can work with instead of simulations that are not worth anything to you at all. People who tell you that you never have to experience any loss have their own agendas in mind. Loss is just a natural part of trading and playing the market, it's not something that can be avoided, just reduced considering with the right product. Just always stay focused on the long term, even if you are experiencing long periods of time where you do not see much profit but rather loss.