Why do so many cars have blown bulbs?

I drive buses for a living. Over the last two or three years I have seen a noticeable increase in the number of vehicles with head/side or tail/brake lights with blown bulbs. Could it be that these particular models use inferior bulbs or that its owners just don't do their vehicle checks each day?
It's because in many cars manufacturers have made replacing the bulbs so difficult they are a garage job.
Answered by Honest John on

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