Life of helmets There's a widely held view that the energy absorbing layer under the shell deteriorates with time regardless of knocks etc. And that it can't be assessed without destruction. Common advice is to replace every 5y or sooner, but there's a few people saying 7y. But I don't know of any studies that give answers at a high level of evidence. There's an obvious risk of bias from those who make make money out of selling them. Then there are platitudes about only being issued with one brain etc, but that doesn't add much practical advice, as opposed to anxiety. If you have intention of competing in near future, then that is a different matter altogether. Do you mean solely about regulations? Jonathan