Hey Simon,
I usually look at my statistics every day. However, it depends on the EAs. If they are active EAs on M1 and M5 and they open many trades per day, you will need to monitor the results daily.
If you go on M15 and H1 it is enough to look at the results 2 times a week.
In my courses, I show different approaches of how to follow their results and keep the top EAs in the live account.
There is no 100% answer to that because it depends on many things and as you know the market changes all the time.
Give it a try on 2 different Demo accounts and see how it goes.