Years ago, learner drivers were advised to check their cars daily or weekly, but these instructions are seldom given or observed these days.
But some car components do deteriorate. Go out on any road in Britain, and it won't be long before you see a car with defective lights. Brake lights, side lights, rear lights, headlights - all fail randomly, or develop faulty electrical connections. And the driver is probably unaware of such failures. In Operational Research courses about inspection and maintenance, electrical items like bulbs are cited as ones which have a constant failure rate after their initial settling down period. So, to a first approximation, they can fail at any time, irrespective of age. OK, some expensive cars do have warning lamps to convey that something is wrong, but most models do not.
Some failures of lights are inconvenient, others can cause accidents. A car with no lights on one side may be mistaken for a motorcycle. A car with no brake lights does not give the following vehicle a warning that it is slowing. I once followed a car at night on a very dark country road whose rear lights had a short circuit - every time the driver hit the brakes, ALL the rear lights went out! I don't know how many accidents each year can be attributed to vehicles with faulty lights. Since every serious road accident costs society many tens of thousands of pounds, there is an economic reason for trying to reduce the number of these.
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