There are various conflicting ideas. . .I think all of them have been discussed at one time or more times on the Forums here.
This is why it is sometimes a good method to have Average Settings and leave things alone generally, and for others that have a good grip on something special they want to use to set the parameters that is specifically good for THAT and then keep a sharp eye on the prices or trends and re-adjust as required.
Market Data 
Markets 
AI
