Let's talk helmets (or lids as I call them).
Helmets are one hit wonders and should be replaced after any significant impact – even if there's no visible sign of damage. They work a bit like a sponge in that they compress under impact to absorb the associated energy/momentum. Unlike sponges though, they don't expand again and only remain in the compressed state. Should you have a second impact in the same area, it can't compress and absorb the impact. You don't need to dent or crack a helmet for it to have done its job. Manufacturers also recommend you replace your lid every 3 years.
MIPS is a nifty feature found in many lids these days, including kids lids. It's incredibly simple and doesn't add significant weight. Put simply, it's a thin plastic liner inside the lid that's designed to reduce angular/rotational forces on the brain in a crash. Think about it, what's the chance of falling off the bike and landing head first completely vertically? You're far more likely to crash with some sort of angular impact which does all sorts of nasties to the brain – not good. For more info, head over to the MIPS website. There are other similar systems such as POC's SPIN.
Of course, a lid won't do much good if it doesn't fit properly! And wearing 3 at once is a bit silly 😉 Here's how to fit it properly: 🚲 Undo the retention dial/adjuster at the back of the lid. 🚲 Stick it on your head so that the front covers most of your forehead, no more than 2 finger's width above your eyebrow. 🚲 Dial in the adjuster at the back so it's snug but not uncomfortable. Tilt your head forward and bring your hands in front of your face. Try and shake the lid off your head – it shouldn't fall off. 🚲 Do up the chin strap, this should be tight enough that you can't get the strap past your chin and in your mouth (kids love this challenge). To tighten, pull the straps “tail” to make it longer. 🚲 Where the chin strap branches out in a Y shape should be just below your ears, adjust the buckle here to fit. Some lids don't have a fit adjuster at the back and rely on different thickness of pads for a good fit. My recommendation is to simply get one with a fit adjuster dial. For kids, check they haven't outgrown their current lid – it'll be obvious if it's too small as it'll sit on top of their head rather than surrounding the whole head. Lastly, you don't need to spend a fortune on a lid. All lids sold in the UK must comply to a minimum standard, look for a CE mark on the box or inside the lid.