Effect on Performance of Adding and Removing Columns

[Xaraja]

I'm not sure how to search for this because I don't think anyone would recommend doing it, but if anyone knows the effect it has on performance, I would truly like to know. I am cleaning up a large number of datasets that I've inherited (almost 400) and I'm finding in many of them that a custom column will be created in Power Query, and then the next step is to just delete that column that was created. This is obviously pointless and as far as I can tell, whoever did this didn't know how to delete the step instead of just deleting the column that was created in the step. 

The reason I am doing this project is because of the problems we have with refresh and query performance with these datasets and I am curious about these wasted steps. Would they have a noticeable impact on refresh time? Would they have any impact on report performance when the user is trying to view and interact with it?

Here's an example in case anyone is curious what I mean:

#"Added Currency BO $" = Table.AddColumn(#"Added BO Prep", "Currency BO $", each if [currencyty] = "US" or [currencyty] = "MX" then [#"BO Prep"]*[salesexrate] else [#"BO Prep"],type number),
#"Removed Columns" = Table.RemoveColumns(#"Added Currency BO $",{"BO Prep"}),

[amitchandak · Accepted solution]

@Xaraja , All calculated columns add to data load/data refresh time. So if the refresh is slow, try to move few of them to source (Like DB query, DB view or table)

remove the unnecessary columns and measures.

The step you shared last.

The first step is adding a new custom column and next step is removing the column use in the calculation of previous step

[Xaraja]

Thanks, I thought that must be the case.