Every scooter goes out with two helmets in sizes that fit, at no extra charge, because a pillion with no helmet is the most common thing we see on this island and we would rather not be the shop it came from.
The helmets are replaced every two years whether they look worn or not, and a helmet that has been dropped hard is thrown away rather than cleaned up.
If a helmet does not fit, come back and swap it. It takes two minutes and we keep four sizes.