Sean Greenwood

Hi all I have to change my water pump on my 2009 2.2D X type. A mechanic has said I should change the PAS pump as well, but I'm reluctant to change a perfectly good PAS pump and spend more than I have to. Apart from the reason of changing PAS pump as I have to take it off to do water pump is there any other reasons to change at the same time? Would it be ok just to replace water pump and continue using current PAS pump? Many thanks. Sean.