Eyal, a captain in the IDF, received an emergency call-up order and is waiting to find out where he is to report for duty. His brother, also an officer in a reserve unit, is already on the northern border. "People go to the reserves for same reason they go to army in the first place - from the deep feeling that despite all these years of existence, we still need to defend our home," said Eyal, who served for a year in Lebanon in the 1990s. Like most of his counterparts, never thought he might ever have to return. The government decided late last week to call up some 15,000 reserve soldiers in case the fight against Hizbullah in southern Lebanon intensifies. Now a routine of good-byes and preparation has set in as reservists find themselves on their way to Israel's most recent war. Some 18,000 reservists have been called up since the beginning of the fighting July 12. The army does not release exact figures on its reserve force, but it is believed to number as many as 500,000. Most reservists are men, who serve until they are about 40. Because of budget cuts in recent years, fewer men serve in reserve units than in past decades. During times of relative peace, a reservist is called for about 21 days annually; during times of war, the call-up is indefinite. During the Yom Kippur War in 1973, for example, reservists were called up for as long as four to five months. Some reservists try to get out of duty, but many accept it as part of living here. "In Israeli society it is part of life, part of the routine, just as there is winter and summer and the holidays: There is also reserve service, it is part of the way of life," said Moshe Lissik, a retired professor of sociology and anthropology at the Hebrew University who has studied the relationship between military and civilian life in Israel. Reserve duty is hardly ever convenient, especially for people with their own businesses and those with young families. "You come because you know that if you don't come your friends will have to work harder, go on more patrols, do more guard duty or go home less, so everyone comes," Eyal said. There is also a feeling of comradeship that reservists often speak of, a feeling of family that springs up after often 10 to 15 years of serving every year together. Some even look forward to reserve duty during less tense times as a time to reconnect with friends and detach from the pressures of everyday life. Now, during a time of war, the feeling is not just one of friendship but national obligation. Dan, 25, a lieutenant in the reserves - and Eyal's younger brother - has been serving near the northern border for about 10 days. He said that after about a week of watching the news on television, he had been anxious to join his reserve unit. After serving in northern Israel in the past, the Hizbullah threat did not surprise him. "I wanted to be part of something already, to do something," said Dan, a university student majoring in political science. "Most of my friends served extra time in the army. We knew that if we were called up there was nothing to do but respond. If we do not go, who will?" He serves with people who are like him, in their 20s, and also those in their 30s and early 40s, many of whom leave behind wives and young children. Shlomi, 40, from Tel Aviv, had thought his days in the reserves were coming to a close. But when he was called over the weekend, he did not hesitate. He said goodbye to his wife, six months pregnant, and traveled north on Sunday. "You see the residents in the North and it really touches you," he said. "There is a feeling of mutual responsibility here that perhaps is different than in other places like the United States where the army is made up largely of the lower socioeconomic classes." In Israel, he said, there is a strength that comes from knowing you are serving with your fellow Israelis from across the country and from all backgrounds. Dan also has no doubts about his path. "Everyone is giving their all and we don't know exactly when we will go home next but we do this out of the belief that what we are doing will help us win the war," he said.