This is so true...I am guilty of this mistake. I am about to solve a real-life problem I have

In- long periods, future, and past...feels better now😃

On- day and dates...Your birthday passed 2 days ago!!!!---Mine is On the 25 of August.

At- Specific time or hours...Nonspecific periods of time...When In things happen at the same time.

Thank you @dansensei.