I've always used some type of timer to keep track of how long students were working on an activity and to keep track of break times between activities. When I first started teaching I did that with an actual egg timer. Later I started using online countdown timer tools. The first one being Online-Stopwatch.com. That's one of the four convenient classroom timers that I featured in this short video.
Four Convenient Classroom Timers
April 14, 2022