Hello, I am new to this forum. And I have a question that may seem dumb to most but I honestly don't know the answer. First off, I am someone with terminal head and neck cancer. I have come to a point in my life where being on my bike is about the only time I feel good, and for awhile afterwards. I just started riding a bike again about six weeks ago. After seven years of not riding, I was quite a sight: had to actually learn it all over again. That is the short version. My question has to do with what seems to be considered important by many which is this: have a tire pump with you when you ride. My question is: unless you are prepared to change or fix a tired when you are out riding, why is a pump useful? If a fire goes flat and you can't do anything about it,the pump seems just something else to carry along. Right? I just want to make sure that I'm not missing something as concerns how bike tires behave. I mean can you have a situation where tires just lose air and there isn't really anything wrong and you just have to inflate? Like in say, this may sound dopey to many but my question is sincere. My Mu P24 has a pump in the seat post. Very cool innovation. And I have a pump for my HPA bike. But why do I have these if I could not repair or replace a tired on the road?