I must admit that I am a slave to my timer. I use it for everything. Years ago when we had a swing set for the boys and their friends would come over, I would tell them that they could have a certain amount of time on a favorite swing, then they would have to let someone else have a chance. I would set the timer and they know that when it went off, someone else had a chance.
I also used a timer on the light in my son's room. As a child, he would get so involved in reading that he would lose track of time and stay up way past his bedtime. I would give him an hour to read, then the light would go off and he would have to go to sleep.
I even use it when I want to sit and read for an hour. That way I'm not distracted by checking my watch. Unfortunately, that is the time when my phone always rings, but I digress.
Years ago, when I was first married and my mother was visiting while I was baking a cake, I set my timer for the recommended minutes. My mother, who was a terrific baker, commented that she never timed a cake. I asked how she knew when it was done and she replied that she knew when she could smell the cake. I was shocked and couldn't believe she could really tell just by the small.
Last week I was baking a cake and puttering around the house while it baked. I was in my office at the other end of the house when I smelled something - it was the cake. About 30 seconds later, the timer went off. I checked and sure enough, the cake was perfectly done.
I guess mom was really right about this.