Typically 1, at least for attractions early in the day. But some FPP are hard to get (ie A&E, 7DMT) and in those cases I take what I get and revise around them. I also try not to have FPP for very late in the day as that limits me from getting additional. That said, sometimes it just makes sense (ie upcoming trip for DH&I does not include a ton of rides that typically benefit from FPP ie Peter Pan and Winnie the Pooh)
I’m in the midst of planning a trip right now, And I have to agree with @OBNurseNH. Normally, I try for early in the day FPPs, with the hopes of additional FPP later that day (my current record is 4 additional passes!). But, as with the new JB and FEA FPPs I just got, I’m lucky I got what I got, and will plan around those!