Usage patterns
日々の〈事〉one's daily ~ (life, work, effort, etc.)
Her daily efforts finally paid off.
日々を過ごすto spend one's days (in a certain way)
He is spending his days quietly.
日々〈動詞〉to do ~ day by day (gradually, continuously)
This plant is growing bit by bit every day.
日々変化するto change day by day
Society is changing day by day.
Expressions
去る者日々に疎しout of sight, out of mind; with time we forget those who have died · friendships fade with distance 去る者は日々に疎しwith time we forget those who have died; out of sight, out of mind · friendships fade with distance