I see very often different EAs being created to trade on any currency pair. However, they are never created or perhaps tested on all pairs. Usually there’s only one currency pair and it’s created and tested on that. But traders still use it on different currencies and see very different results. I believe it only makes sense to have a EA created for one pair and trade with it on that one special pair all of the time.
That is what Forex Brilliance review creators think too and they have created a suit of robots that trade on explicit currency pairs. There’s no confusion in regards to what to trade it on and whether it should work better on one pair or another. I suspect more developers should use this practice.
Not just that, when you’re trading manually, you need to consider that for your manual system also. It is a matter of probability, after you test and tweak a system on one currency pair, it’s likely to perform better on it. Naturally, I do not say that there are no systems that are universal, but it is’s a lot more difficult to make and run such a system.