Sunscreen does its job invisibly, and you only notice when you skipped it. Good habits are like that.

Prevention is invisible by design, which makes it hard to stay motivated about. Nothing happens when you do it, and the reward is a bad thing that quietly failed to occur, so you get no feedback except on the day you forget. That is why flossing, stretching and saving all feel pointless right up until they do not. The absence of consequences is the result.

Choose one invisible habit and attach it to something you already do without thinking, like brushing your teeth or dropping your bag. Keep it two weeks without looking for a payoff, and judge it by the trouble you never had.