45 minutes should be good. But check-in when you get there then relax too many wait till 5 -10min before, to check in. If you check-in online or in person at the airport with time to spare.You will have time if there's any changes in your connections they have time to work them out.
I agree with Doris. 45 min would give u enough time at IPT.
There really isn't a set answer but most people would say at least 45 minutes before. This is a very small and simple airport so there are not usually any difficulties you would face at larger airports.
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