Originally Posted by FlyerJ

If you care where you sit, or if you want to sit together, you absolutely need to select seats in advance.

And that means you’ll need to pay for seat selection.

Originally Posted by maxjasper

I never leave seat selection to chance as usually airlines seat Basic passengers in worse seats like window seats. Best is to pay for couple of favorite seats you wish be together and eliminate all worries. At check in you can then just pay for your baggage if you have any.

Originally Posted by WJter

The time of when you check-in won't really matter, basic Fare seat assignments are done prior to the 24-hr check in window. That said, I'd still recommend checking in 24 hours prior, because if you aren't seated together you'll have more selection to switch to (for a fee).