Time Observation

As I sit on the bed in my room I notice that there are many different ways to keep track of time: - 20 seconds pass between the blinks of the smoke detector - It is 10 am when I hear the weed whacker going on outside my window - 4 hours have passed when my laptop runs out of battery - 15 hours have passed when my iphone runs out of battery - 2 days have passed when we must fill the air mattress back up that we are currently sleeping on - 1 week has passed when my wife vacuums the carpet - 1 week has passed when the bed sheets are washed - 4 months have passed when the carpet is professionally cleaned