Would the countryside be totally devastated with burning fields and villages and hanging corpses everywhere, or was it customary to leave the peasants alone, maybe only demanding tribute and rations for the troops? If there are instances of both extremities, I'dd be really happy if the background to that kind of behaviour could be given.
:edit: To clarify, I'm mostly interested in the negative effects of the passing army, and how commonly they happened. I don't care whether this strain was caused by a hostile or friendly army.
Are you talking about an hostile army or a friendly army just marching by?
Your question is too vague, because you are talking about many cultures and situations over thousands of years.
But, to give you a smörgåsbord of possibilities...
some armies had their own supply trains following them, and they had little impact on the native people
some armies traveled light, and bought food and supplies from the native people as they went along
some armies confiscated food and supplies on the march
some armies were ordered not to pillage and the soldiers were expected to only accept wages
some armies were allowed to pillage as part of their pay, or to punish the local population
One of the drawbacks to allowing an army to pillage is that they would sometimes not want to leave a city that they were having fun with. Or sometimes they would disobey orders and attack the wrong city that seemed to be rich plunder. Those are a couple reasons that enforcing soldiers not to plunder was common, because you might lose control of the troops. You want them dependent on your pay, if you are the leader.