I'm still in the middle of my weekend experience.
When the retreatants arrived, one of the announcements the director made was that they would have the gift of a "timeless weekend"; they were asked to give up all electronic devices until they left on Sunday morning. Of course, the members of the retreat team can't have timepieces, or the effect would be lost.
Most of the activities are done as a group, so we rely on the directors to tell us where to go and when to be there. When necessary, someone rings a bell to signal gathering times. I never thought about how the directors kept things on track!
One of the activities I'm leading had to end after a certain amount of time. My first plan was to use background music, and listen for the end of a selection to know when the time was up. However, it was decided that the activity should be done in meditative silence.
When I asked how I would know when the time was up one of the directors told me, "look at a watch!" Today I used a watch when it wasn't technically allowed.
I certainly couldn't have the watch on my wrist, but I put it in my pocket until I needed it. During my activity, I sat in the back of the room and surreptitiously glanced at it now and then. Nobody was the wiser!
When the correct amount of time was up, we moved on to the next activity.