To answer your question, no people don't usually get nose bleeds for "no reason." However, there are some fairly common reasons that I can tell you about, and they don't necessarily involve trauma to the nose. Epistaxis (medical term for nose bleed) can be due to numerous different causes. Bad things like tumors (very rare), and hereditary disorders (like HHT...Hereditary Hemorrhagic Telangiectasia) can cause bleeding
. But much more commonly it is due to trauma or drying within the nose. The lining of your nose (mucosa) is much more vascular than say the skin of your hands. When the skin on your hands dries out and cracks, it may bleed a tiny bit, but it stops quickly. If the mucosa in your nose dries out and cracks, it will bleed much more robustly, and for longer. In particular there is an area on the septum (divider that goes down the middle of the nose) where a number of different blood vessels come together. This area is called Kisselbach's plexus, and since it is anterior on the septum, it tends to dry out and cause the majority of nose bleeds. I would recommend making an appointment with an ENT to get your nose checked out to make sure first of all that it is nothing serious. If they think it is just due to drying, they may give you some nose sprays, or a cream, or they may even just cauterize it in the clinic. I hope that this was helpful. Best of luck.