Verbose
Deity
Not if we are talking pre-Marius republic army (though experience they might have had, granted, considering the amount of warfare Rome engaged in and expected its plebeian citizens to put up with). The Romans butchered at Cannae were citizen-soldiers after all, not professionals. And that was a big reason Rome soon fielded a new army. Had they been full professionals, that would have been it. I mean, Hannibal's army was the professional one when compare to the Romans of the day.Remember Hannibal? He slaughtered the Romans, in several battles and still, he lost. Because the Romans could field another army as soon as one fell in battle.
The Roman army was composed of professionals, most had decades of military experience.
Well, that does depend entirely. There certainly were professional mercenary troops in western Europe beginning in the 12th c. Otoh the iconic kind of feudal heavy cavlary we have come to expect only really spread with feudalism, which did depend largely on the French kingdom extending its reach from the heartland of feudalism in northern France, England and the German Rhineland.A Medieval Army, had a small section of elite knights, who trained from youth to be a warrior (not bad), but, the majority of a Medieval Army was composed of peasant soldiers. Most of whom had no combat experience, armor or a decent weapon.
In fact 12th c. Italy seems to have led the way in the professionalisation of warfare. A lot of the mercenary bands on the HYW would in fact seem to have had parallels prior in Italy, in the struggle, often military, between the Papacy and the Hohenstaufen emperors, which of course ended with the Papacy calling in the French Angevin empire to give the Hohenstaufens the chop, incidentaly also leading to an extension of French-style feudalism to southern Italy.
Northern Italy with its city-states were a different order entirely. I doubt the local great powers like Venice kept itself woth sub-par forces in general, though in their case power was mostly maritime. Otoh the land-based great power was Milan, and Milan was capable of fielding a citizen-soldiery of something like 30.000 men. It even became a Medieval saying, "The were as numerous as the host of Milan", i.e. they came in numbers beyond measure. And incidentally the citizen-soldiery of Milan did smash various Imperial knightly armies time after another. Considering the warlike stance of Milan as the leader of the "Lombard League", these men also had a lot of combat experience.