over time

Gradually throughout an indeterminate of time. I know you think spending a few bucks on a coffee every morning isn't a big deal, but it will add up over time. When I first met Ben, I thought he was a cocky jerk, so I had no interest in dating him. But as I got to know him over time, I slowly fell in love with him. They built the old house on a foundation of sand. Unsurprisingly, it sank into the ground over time.