one by one; each; every; at intervals of
day by day; every day; by the day
at every opportunity; for each and every thing that crops up; with every little thing; whenever possible; whenever the chance arises; at every turn
day by day; with each passing day; as the days go by
with each person; with everyone
every day and every night; day after day; daily
year after year; as the years go by; with each passing year
in its entirety; whole; wholly