1)
What do we learn from "Yom b'Yom"?
1.
Ibn Ezra: Each day [they read] what pertains to that day 1 .
1
Some Mitzvos (e.g. Sukah) apply all of Sukos. Some are only for the first day (Arba'as ha'Minim outside the Mikdash). Some apply to other days (each day has its own Korban; Arba'as ha'Minim near the Mikdash, Nisuch ha'Mayim (some say that it is only on some days of Sukos), Shabbos...
