Romans and Swords

I'm curious as to how many pila the average Roman soldier carried into battle. And did he throw them all at the enemy as they charged? Or did he keep one to repel cavalry attacks? Did Marian legionaries (and legionaries later in the future) use the hasta anymore, or was it just carried by auxiliaries?

2 in the beginning and by Julius Caesar's time, I believe it was only one. They threw them all before making contact because it's impossible to hold the scutum and pila while fighting.

But not all legionaries of a maniple/cohort actually fought. Please forget the change of the rows during fight with the centurio using a whistle or something like this. The soldiers in the back rows could keep their pila. We have some reports that suggest a constant use of pila also during prolonged battles. When one of the frequent pauses of the close combat occured, pila could be given to the front lines or soldiers from behind could throw. Or perhaps even the soldiers could change rows, but that would have been a very dangerous manouevre.

I've not much knowledge about the later -boring- Roman professional armies. But in the legionary forts lots of heads of lances were found, so I believe of a constant use of the hasta not only in the auxilia. But experts could tell you better.

I recall reading that most legionaries had two pila, but each would only carry one in battle at a time - already for the rather practical reason the scutum had a horizontal grip, so you couldn't really hold something long and pointy in the same hand (as conversely the Celts and Germans tended to with their vertically set grips). But since infantry slugging matches tended to take a long time and there were many lulls when both sides stepped back th catch their breath and reorder the ranks, resupplying fresh ones should have been easy enough.

In the age of overseas expansion that we are most familliar with, the standard seems to be two pila per legionary, one light and one heavy which replaced the hasta for all except the triarius. Both were hurled with good effect in most of the accounts we have of the period.