Question about comps for a rehab

[Nick Dunin]

So Im watching a lot of BP youtube videos.  One of the videos was talking about how to figure out how far to take a rehab, how much should you put into the finishing touches.  Like the type of countertops, or backsplashes etc...  And that thats all based on comps.  So Im seeing a lot of videos that say "that's what your real estate agent is for".  Now these guys work for money obviously....so do I pay them for comps?  Am I expected to use them sell or buy a property at some future time?  How far can I use them before I they expect a return for their time?  
Any help on this is appreciated!  Thanks.!