City of Cheyenne Fire Inspector Byron Mathews is urging people people to check their smoke and carbon monoxide detectors when they change their clocks this weekend. Mathews says now is an especially good time to make sure your detectors are working properly because the threat from fire and carbon monoxide tends to be greater in the winter months when people spend more time indoors. He says in his career as a firefighter he has seen countless examples of the detectors saving lives. The time officially changes this Sunday at 2am, but most people set their clocks back  before going to bed on Saturday night.