Just to add something else.....If you have BIDS Helper installed (https://bidshelper.codeplex.com/) then if a data type/size changes in the source, after refreshing the DSV you can use the Dimension Data Type Discrepancy Check (https://bidshelper.codeplex.com/wikipage?title=Dimension%20Data%20Type%20Discrepancy%20Check&referringTitle=Documentation) to quickly update dimensional metadata so that it's in line with the source. Saves having to go into each attribute and manually change them.