Trust me, I know all about that. I took a buddy to Nicaragua this past fall and originally booked a nice, simple DEN-MIA-MGA on AA using miles. AA postponed their return to Nicaragua and there aren't any OW partners that could get me there. So, booked a nice easy DEN-IAH-MGA with UA miles. Then of course United postponed their return a couple of days later. So, then I found DEN-IAH-SAL-MGA with the last two legs on AV, but AV stopped flying IAH-SAL on Wednesdays, the day we had to leave. Rebooked DEN-DFW-SAL-MGA, same story with the DFW-SAL a couple of days later, cancelling their flight on our specific day. Finally ended up flying DEN-IAH-PTY-MGA after convincing a couple of UA agents that they should look kindly upon us and open up space on the UA IAH-PTY flight once a glimpse of PTY-MGA space opened up. I think, overall on that trip, I had 8 or 9 schedule changes in 3 months. Each made it more complicated. Flying to India this summer, I purposely scheduled a few >9h layovers to a) let me see something of the cities where I'm laying over, and b) to provide a buffer in case of big schedule changes.