When to change your rear light cluster bulb
“You risk being pulled over by the police and face a possible fine”
Having a fully functioning set of rear bulbs is important if you want to avoid someone careening into the back of you, so you should replace rear light bulbs as soon as they fail.
You also risk being pulled over by the police and face a possible fine, although you’ll usually be given a few days to replace the bulb (and prove you’ve done it) before facing further action.
All cars are slightly different, so if it is time to change your rear light bulbs, find your car for specific instructions.