There was sort of a “season” for campaigning, let’s say roughly the six months from April to October. But there wasn’t really anything like the modern concept of a “tour of duty”, and the amount of time you spent on crusade depended on a lot of things - whether you were there on one of the major expeditions (the ones we usually give numbers to today), or you were part of a small expedition or an individual pilgrimage, or whether you could afford to stay there for a long time, or whether you had been there before or your family had a tradition of going of crusade.

First I should note that after the First Crusade, there were crusader states in the Middle East, and they had their own armies that were sometimes dependent on reinforcements from Europe, and sometimes not. They usually campaigned during the summer, and although they could campaign throughout the rest of the year as well, they tended not to, due to the weather and due to agricultural needs. You couldn’t keep an army out in the field forever since most of them weren’t professional soldiers. If they had to go home and farm, they would just leave.

Armies that arrived from Europe, would also typically have to arrive between April and October, if they came by ship, because of the weather on the Mediterranean. The First Crusade famously walked the whole way, and the main parts of the Second Crusade also travelled by foot, but that took much longer and went through dangerous enemy territory. So after the Second Crusade, most crusaders usually arrived in the east by sea. If you leave Europe in April it would take 5 or 6 weeks to cross the Mediterranean, and if you wanted to get home again you’d have to leave in September or October, or you’d probably be stuck there until the next spring when the sailing season started again.

No matter how you got there, technically all you needed to do to complete your crusade was to visit the Holy Sepulchre in Jerusalem. You didn’t even have to fight anybody! After the First Crusade, nearly everybody felt that their vow was fulfilled, so they simply went home. A couple of years after the First Crusade, there was another wave of crusaders (sometimes called the “Crusade of 1101”), and a lot of those crusaders had also participated in the First Crusade. The most notable is probably Stephen of Blois, who had fled from Antioch during the First Crusade. His family shamed him into going back, and this time he died in battle.

For the other crusades, you could probably expect to be there for a couple of years. On the Second Crusade, Louis VII of France besieged Damascus along with the army of Jerusalem in the summer of 1148. When the siege failed, most crusaders simply went back home. Louis himself stayed in the east over the winter and sailed back to France in April 1149.

One of Louis VII’s fellow crusaders was Count Thierry of Flanders, who stayed until 1150, and then returned to the east again from 1156-1159 and 1164-1166. Thierry’s son and successor in Flanders, Philip, continued the family tradition and went on crusade from 1177 to 1179. So in the case of these individual pilgrimages (not part of a bigger crusade movement), they might stick around for a 2 or 3 years before going home, and some people came back more than once.

Another repeat crusader is Count Stephen of Sancerre, came on a pilgrimage in 1170, but only stayed for six months, i.e. the length of just one sailing season/campaign season. Both Stephen of Sancerre and Philip of Flanders returned on the Third Crusade, and both died during the Siege of Acre in 1190 and 1191.

For some 13th century examples, Emperor Frederick II was only in the east for less than a year, from the summer of 1228 until the sailing season began in April 1229. But Louis IX spent six years on crusade, from 1248 to 1254 - some of this time was spent in captivity in Egypt, but for four of those years, he was just hanging around, repairing city walls and castles. He went on crusade a second time too, in 1270, but that time he died after only a few weeks.

So it was fairly common for people to go on more than one crusade, but sometimes it depended on whether or not there was a strong tradition of crusading in your family. Your “tour” might depend on the sailing season, so if you could get back before the sea became too rough in the winter, you might spend only a few months there. But if you got stuck there, or you could afford to stay as long as you like, your crusade/pilgrimage might last 2 or 3 years or more.

Sources:

R.C. Smail, Crusading Warfare, 1097-1193 (Cambridge University Press, 1956, 2nd ed., 1995)

Christopher Marshall, Warfare in the Latin East, 1192-1291 (Cambridge University Press, 1992)

John H. Pryor, ed., Logistics of Warfare in the Age of the Crusades (Ashgate, 2006)

Nicholas L. Paul, To Follow in their Footsteps: The Crusades and Family Memory in the High Middle Ages (Cornell University Press, 2012)