Hi Bob,
Here is what I do:
If the current EA I am trading have been profitable over the last one to two weeks it tells me the EA is in a profitable trend and I want to continue to let it trade. I would only replace the EA with new EA if the backtest shows it has been more profitable over the last one to two weeks.
If I have an EA with a DD I would look to see how long it has been in a DD. If the DD is only for one or two days I would keep trading it as all EAs will have periods of DD’s and then continue on to be profitable. However, if the DD is more than two days then it is telling me the EA is in a downward trend and I would replace it.
Alan,