The Sengoku period is generally described as one in which daimyos waging war on each other was common, but was it really that common, or just far more common than at other points in history? Obviously the Onin War and the unification of Japan had large scale civil warfare, but between those, how much did a given daimyo need to fear his neighbors?
Along the same lines, just how many daimyos were there during that period? Did they roughly follow the pattern of the shugo system, or were daimyo who controlled multiple provinces or tiny fractions of a province common?
War was very common, both large-scale and small-scale.
Kujō Masamoto's kept a diary when he ran his Hineno estate in person between 1501 and 1504, the contrast is clear. In less than three years at Hineno, Masamoto recorded two local lords and two competing temples regularly fighting in the area. Both lords and at least one temple demanded taxes and provisions, kidnapped people to use as hostages, threatened to burn villages and markets, actually burnt villages and markets, forced villagers to work as porters for their armies, fought the villagers, and fought each other. People escaped into the hills, came back to try to farm, only to escape again, and then came back again. People resorted to banditry or joining armies to get food. There was dought and famine, and the people were trying to trade straw for grain, ash for fertilizer, and digging bracken roots for food. Masamoto himself tried threatening to call the Bakufu, bribing the warriors to leave them alone, threatening to just let them burn everything, but the marauders just kept coming back. He once had to flee to the hills himself, and basically had to abandon Hineno and go back to Kyōto in 1504.
While this was during the height of misery between 1490 and 1520, warfare didn't end until at least 1590. To use two famous examples, between 1541 and 1569, Takeda Shingen was not on campaign outside of his home province of Kai in only five years. His rival Uesugi Kenshin in comparison missed only four years between 1555 and 1576. That's not counting internal conflict. For instance Kenshin missed 1556 because he was home in Echigo crushing Ōkuma Tomohide's rebellion.