I'm doing my first ever ex-EU later this year using DUB as my starting point. I am not overly familiar with DUB and am generally a more cautious person by nature so I planned an overnight in DUB prior to the 0850 flight without any consideration to doing a back-to-back.

As others say, the extra money is well.spent as an insurance. Rather than get the last flight to DUB I will be on the 1850 to allow a quick trip into town for a couple.of beers to start the whole trip off. It'd be rude not to wouldn't it?!