I know many people who get value from a simple tool called the Pomodoro Technique.
It's a time management technique used to break work into periods of activity separated by short breaks. Each activity period is called a pomodoro. Why "pomodoro"? The technique was developed by Francesco Cirillo, who named the technique "pomodoro" as a nod to the tomato kitchen timer he initially used.
The technique has come a long way from those humble beginnings with phone apps, web versions, etc. I decided to make a simple hardware version in CircuitPython with a rotary encoder to set the time and mode!