Jen sees him just as Daylight Saving Time kicks in and her phone switches from 01:50 to 01:00. She hides a smile; thanks to the clocks going back, he is deliberately no longer late.”
-- Narrator (Day Zero, just after midnight )

Importance: Jen cites this as being typical of Todd's nature. This is also one of the first looks at the irregularities of time that is a central part of this story.

If tomorrow will be yesterday, does anything matter anyway?”
-- Narrator (Day Minus Two, 08:00 )

Importance: Jen is just settling into this reverse time, and the probability that nothing matters is one of her early fears.

It is so strange for Jen to witness this; the things that happened while she was lawyering, while she was buy caring too much about work and – clearly – not enough about home.”
-- Jen (Day Minus Two, 19:00 )

Importance: Jen is just beginning to realize that Todd expects her to be somewhere except at home with him, meaning that being away has become the normal situation...