How often do you lose you balance and what direction if I may ask? Not sure how I'm supposed to hit my head on a bike unless a car hits me. If you lose balance that often leave it at home.
Helmet is good especially for the latter reason but a bicycle goes 20kmh and if you fall you don't die, just get your knees hurt or something.
Once in a bad situation is enough for permanent brain damage. Another bike or a car making a sudden move, someone hitting you, etc. Curbs and cars provide for dangerous landing spots if you fall.
I know of two separate people who were biking as a part of their daily commute without a helmet, and woke up in the hospital with zero recollection of what happened, but multiple issues (such as one of them being unable to concentrate or remember things).
So did the two seperate people fall, or get hit by a car?
I know zero people who hurt themselves badly on a bike, but I know two that got hit by a car as pedestrians, so going with my anecdata walking is much more dangerous than biking
You don't hit your head on the bike, you hit it on the concrete or a curb. Roads can be slippery, material failure is possible. The speed of the bike isn't that much of a factor, it's the object under you preventing you from effectively mitigating the fall, or making it worse.
I fell twice recently because of slippery roads just as you're saying. Both times my head was far far away fron the floor, I only hurt my palms and knees both times.
I still don't know how you're supposed to fall head first onto a curb unless you tie your arms behind your back.
