Hello Jacpin,
yes, it is good to have couple of EAs ready because sometimes it might happen that few of your EAs on real account lose. And if you have ready ones, you just replace them, and if you do not have you will lose few more days until you prepare them and test them…or even weeks.
EA Studio really gives freedom to the trader not to be limited with the number of EAs he is using.
Imagine you buy EAs from the market, you will be far away from what you are doing now, and you will need spend thousands of dollars, and still you will not have so many EAs daily, weekly, monthly.