"
In practice I have never, ever, had anyone abroad show the slightest
interest
in anything I have got in or on the car. I do try to take most of the
above,
but I don't carry spare headlight bulbs - they're expensive and I've
never
had one fail in the last 20 years or so. Also I've stopped putting those
nasty little stickers on my headlamps - I'm not convinced they do
anything
and nobody's complained (so far).

Properly designed, and fitted, headlamp stickers do work effectively

You may be right but I'm not convinced that the 'one size fits all' little
plastic discs on sale at Halfords and the like, meet either of your
criteria.
Even if they were 'properly designed' I imagine the precise position of
the
sticker is vital. The instructions consist of the usual incomprehensible
diagrams so in the end one just has to guess and hope.

You need to use the ones designed by the headlamp manufacturer not a one
size fits all type.

Peter Crosland