We have seen lines at cape air that resulted in over 45 minutes to check in and get boarding passes. At that time cape cape was not participating in TSA pre +. The security line was painfully long. Hence the buffer. From time to time flights leave eis late due to weather etc. I have had this add over an hour.

If you are departing during the winter from a city in the north, then p, de-icing can add another 30 - 45 minutes of delay to the whole process.

So far, the only thing really reliable has been getting through usa customs in sju with global entry.

If I am flying on one ticket, then I don't mind the tight connection, otherwise I worry about missing my connection and the potential problems and costs are mine.