Ok so I just remembered this and I'm not sure if it's been mentioned before so I didn't want to highlight it with its own thread but I did want to share:
We did our fastpasses before we left like everyone else. Since it wasn't a busy week, we did it based on the lines that are always long: Mine Train, Test Track, TSMM, Peter Pan, you get the point. My kids aren't thrill junkies so we didn't need FPs for ToT, RNRC, etc. Anyway, since it was slower the 3 we got were pretty much enough for the day - the other rides already had 15 minute waits so FPs were unnecessary. Until the last day. MK was busier, we got there around 10 after checking out of the room and we had FPs for Pooh from 10-11, HM from 11-12, lunch at the Plaza at 12 and Buzz from 1-2. But I realized we should leave the park NO later than 1:30 to be sure we were back for DME at 3. So I had to get creative and here's where it gets interesting. After checking into Pooh, before we even boarded the ride, I pulled out my phone and adjusted the HM fastpass to 10:30-11:30. When we got off Pooh we rode the Carousel and got to HM around 10:30. After scanning at the FP reader before we even got into the stretch room I pulled out my phone and adjusted the Buzz FP to 11:00-12:00. We rode HM, went to Tomorrowland, rode the Peoplemover and checked in at Buzz at around 11:30. We rode Buzz, checked in at The Plaza a little before 12 and were seated shortly thereafter. Had we been spending the full day we would have hit the FP kiosk before lunch. And not everyone needs to be at the kiosk. If you are linked together one person can make new FPs for all. I don't particularly care for the fastpass plus system but if you know how to work it - namely being able to adjust times and not need to wait until you are through the ride to do it - it can really work to your advantage.