Many seats are thinner and narrower than in the past, and planes like some 777s, which used to have only nine seats across in coach, now cram 10 across.
If you're busy, you might be tempted to put off your studying and cram in a big chunk of learning once every week or two.
But it depends on the goal; if it's to memorize a speech in a day, you'll probably want to cram more intervals than if you want to remember something five years later.
It's like I try to cram all of these tasks -- for instance, starting a company, winning the lottery, getting a book deal, creating a TV show, etc.
