E-scooters and e-bikes are becoming more common in Israel. About 90% of riders of these vehicles don't wear a helmet.
Wearing a helmet while riding a (regular!) bike reduces the risk of head injury by up to 85%. The law requires the wearing of a helmet only when riding an electric bicycle, and the fine for not wearing a helmet increased about a year ago from NIS 250 to NIS 1,000. A few days of dull headache - that was the only price I paid for a stupid accident.