There are obviously very few DIY types here - 'cos if you were, you'd have worked out the cause of the problem of duff headlamps yourselves.
Just go and try and replace the bulb in any modern car. Go on - I dare you! Remember, it will almost certainly be a halogen bulb that you must NOT touch with skin and you need arms like an octopus to gain access to the rear of the housing
Some cars advise it as a main stealer job!
Then, when you look at the costs - and weigh that up against the fine and the potential for getting caught, it becomes blindingly obvious.