Don't worry too much about me! I check my helmet over quite carefully on a frequent basis, and replaced my last one just as soon as I saw a crack. I don't mind replacing frequently; under these conditions I don't expect them to last for a year. (I'm glad that the safety certification is the same, regardless of price!)
I used to clip the helmet to my bag, but it seemed to get banged around even more. I'm a university student and have nowhere to store anything during the day - we can't even leave our things for a minute in the library if we get up to go pee, due to very real theft concerns. I'm really looking forward to graduating and finding a job with a desk to call my own![]()
soprano, if you invest in an Arkel Bug backpack pannier, you'll have a place to put your helmet (there's a handy helmet holder on the outside of the pack). It costs the same as a couple of helmets (it's gone up since I looked at them first years ago), so you might actually save money by not having to buy a new helmet every year. Helmets might be damaged even if you don't see cracks.
Just some thoughts, from someone who was in an bike accident and had to be airlifted and takes helmets very seriously.