Depends on the situation/sport.
In baseball I always want my team to draft pitchers early.
In football I usually say BPA, so many injuries in that league that depth is crucial. Also thats a league where you can play 5 WR's at a time for instance so having some redundancy isnt a huge deal if the BPA isnt necessarily a position of need.
In basketball, if you are competing for a title and one or two pieces away go for need. If you arent competing for a title, take BPA and hope they turn into a star or can be packaged for a star